Tobirama's ideas
Tobirama knew that if he wanted permission from all thirteen Clan heads, he would need very thorough reasoning on why Edo Tensei would be beneficial and the systems that would be in place to ensure the proper use of Edo Tensei (Tobirama may not understand other people's resistance to 'disturbing' the dead, but he was smart enough to know he had to mitigate it).
Now, first to ensure that other countries, or other shinobi villages, do not band together to wipe out Konoha. Either playing off the Edo Tensei as a hidden clan who decided to join Konoha, or having a shinobi force 'above' the regular ninja ranks which would be the 'hidden' members of the village; given the more risky or difficult missions. Personally, Tobirama preferred the shinobi force, but he would present to the Clan Heads arguments for both, just in case. The regular shinobi ranks had been created to ensure the formation of teams between the various clans and families that would have a similar power level. Internally, some clans had no standard power rankings at all, but most did. Those were based on different standards for each clan, so everyone had to come together and determine standard Konoha ranks that would help with resource utilisation and management. There were three ranks: Genin, Chunin and Jonin. The beginner Genin level required the use of what had been termed the Konoha Basic Three - a disguise technique, a clone technique and a displacement technique. In the future, once an academy was up and running, Tobirama was sure that those would be defined as an actual jutsu instead of the general guideline, ensuring proper standardisation and encouraging a more complete sense of belonging to Konoha (perhaps developing a displacement technique for leaves? That would fit with the name...). Beginner Genin also required a theoretical test, to ensure a basic understanding of Kanji (some lower clan members only knew hiragana) and to assess survival knowledge. Some clans had also wanted to include standardisation of weapons (kunai, shuriken, some familiarity with senbon), taijutsu, genjutsu and even standardisation of fuinjutsu - but that would have to wait for the future. Chunin qualifications had a broader guideline due to Clan specialisations; more if/then statements than standardised tests. They were in between Genin and Jonin, either too broad of a skillset with not enough power or too specialised to be useful outside specific tasks. Jonin had strict requirements that would develop Konoha's top shinobi. Firstly, they had to have started on at least two different elemental manipulation exercises. Secondly, they had to have at least one jutsu of each element, one genjutsu, two taijutsu styles, familiarity with kunai, shuriken and senbon, a minimum of twenty jutsu in total and possess some first aid knowledge. Thirdly, they must be able to work in a team, regardless of who was present from which clan. Finally, they had to pass a minimum fitness test, first with chakra, then without. Obviously, as standardisation occurs, the standards would be raised higher, but at the moment, this ensured there was enough of the highest Konoha shinobi rank from each clan to not cause offense. ANBU would technically be above Jonin in rank, although it could hold anyone. As it would be a 'hidden' force to the rest of the world (perhaps even to most of the village?), members would be covered in camouflage gear, with a full face covering or mask that hid the eyes. Hair could be shown, but the uniform would have the option of hiding it. This would serve the purpose of hiding the abnormalities that Edo Tensei showed on the revived. As a 'stealth unit', their names would be unknown (if masks are used, perhaps some theme could be painted on, providing a basis for codenames...) and any chakra abnormalities could be accredited to ensuring anonymity. Of course, it would be better if there were some non Edo Tensei members, ideally recruited from the Jonin force, that would eventually be identified. Intel leaks were normal in the shinobi world; it was better to have less important information dangled out for others to take than for the Edo Tensei to become public knowledge. Of course, Tobirama mused, the most important question would be: who do we bring back and why? For that, he had already designed legislation and fail-safes to be put into place. Firstly, those eligible (the criteria for this would fluctuate depending on circumstances, but by a general rule - unique, powerful or dying art, and in compliance with the complete Edo Tensei's requirements) would be made aware of the jutsu and be given the option of signing a contract: either 5 years or 10 years of service as an Edo Tensei (hopefully this would mitigate any concerns for slavery the Clan heads would have). Tobirama would prefer if the candidates were made aware of the jutsu after their death. That is, they would be summoned and offered the chance to sign the contract. This brought up an important concern: control. As a fail-safe, every Edo Tensei must be under the control of the summoner. But that brought up the question: couldn't the summoner force the Edo Tensei to sign? For this, Tobirama had already changed the jutsu so that speech could not be controlled. Of course, the summoner could stop the Edo Tensei from speaking at all, but if given the ability to speak, the summoner could not force them to say something specific (I'd have to find a way to mitigate blackmail, to ensure they can choose as freely as possible...). So, to sign the contract, a rotating group of three Clan heads would need to be present and receive verbal confirmation that the candidate would sign the contract before proceeding. The contents of the contract itself, could perhaps be specific to each shinobi, or it could be generalised. If specific, it would require the three Clan Heads to witness what the Edo Tensei wanted: this could be in regards to specific mission types, where payment went and to whom, whether they would record non-Clan specific jutsu, or teach their specialties to others. If generalised, there would have to be specific contracts they could sign: an 'everything' contract, where they agree to go on all missions assigned and will teach or record when requested, a 'mission' contract, where they agree to go on all missions, or a 'teaching' contract, where they agree to either mentor or teach other shinobi their skills. After the end of their contract term, they could decide to rest or agree to another contract period.
Tobirama had created as many scenarios as he could think of for the use of Edo Tensei, trying to create fail-safes and mitigation strategies. There was just one obvious problem: corruption. Tobirama did not want Edo Tensei to be used to enslave the dead because of the likelihood of the jutsu being used on himself or his loved ones, amongst other worries. Edo Tensei, especially a complete version, could be widely misused. An army of immortal, unstoppable shinobi could be used for world domination, to enslave unwilling shinobi to become tools for a corrupt summoner. He had plans in place for that: multiple summoners (ideally, the Clan heads, but having their clan shinobi revived in equal amounts under the other summoners, to ensure they care about Edo Tensei misuse), multiple investigation committees into the potential coercion of Edo Tensei (composed of Edo Tensei, none under the same summoner, and one non-summoner shinobi), along with various checkpoints and balances within ANBU itself. Tobirama had also incorporated protections within the jutsu itself: any attempts to modify the control tag, cancels the jutsu. He was also working (theoretically, which was very annoying Anija!), on incorporating some form of inherent knowledge that lets the Edo Tensei cancel themselves. This aspect was especially important, as Tobirama had no idea what would happen to the Edo Tensei when the summoner died. Would the jutsu cancel itself? Or, would it keep the Edo Tensei ongoing (this was most likely, based on how the jutsu worked, but again - only theoretically). In addition, this would hopefully eliminate any misuse, unless the summoner forbids the Edo Tensei from using any handsigns at all (a possibility, especially if only to be used for knowledge, taijutsu, kenjutsu, fuinjutsu, or other non-combat ways...could civilians ever be a candidate? Perhaps for a dying art? I suppose an inexhaustible workforce may be enough of a reason for some).
Regardless of his musings, only by getting permission from the Clan Heads would he be able to move onto practical experiments. Tobirama was sure many more uses could be discovered through either trial and error or systematic experimentation. (What if an Edo Tensei used Edo Tensei? Theoretically, it would work - but would the first summoner be able to control the 'second generation' of Edo Tensei? I should probably determine that personally...) A sudden thought hit Tobirama, an angle he hadn't thought of before: what if an entire portion of ANBU was responsible for research and development? Jutsu, chakra exercises, forging techniques, crafting techniques, fuinjutsu! They would have to have a research centre outside the village, to mitigate any disasters but... the possibilities! There are hundreds of jutsu, fuinjutsu and chakra ideas that have been discarded due to the extreme theoretical danger to the creator - one that Edo Tensei would mitigate. Even civilian aspects of R&D would be useful, such as technology and agriculture. What about medical aspects? Could the Edo Tensei perform research on themselves, determine the effects of poisons and diseases? So much potential... I have to include this in my speech to the Clan heads.