Hello everyone. So, if you have read my prior work and liked it or read the tags and liked it, please stay for this one. As you can tell from the description, I've scrapped all of the HP canon except for the parts I wanted, so this is just a plot explanation.
Before we begin, I want to preface this with a warning. First, my content is going to be triggering. There will be themes of child abuse, neglect, smoking, violence, self-harm, mental illness, terrorism, death, and grief. Secondly, my future work will be way better than my first one. I am honestly ashamed of the writing of that one. I rushed it too much, causing me to speed through the plot and the grammar, making it sloppy and underdeveloped.
My changes to the first book are the following. First, I don't know if Surrey is close to London but bear with me.
As we know, the Dursleys let Dudley do whatever he pleased, and they also wanted Harry out of the house as much as possible. That's why I think that since they would both be out of the house, Harry getting kicked out, and Dudley controlling his little gang, it makes sense the two would end up in London. Yes, that would surpass the Blood Wards, but they really weren't necessary. The only time the Blood Wards ever protected Harry was when the Death Eaters knew he would leave them.
Secondly, I think Harry would be more of a reader than he was. Not only would a library be a safe getaway for him while being hunted by Dudley, but in a way, reading would be also. Considering that you are reading this, you would know how great of an escape reading can be from distress or abuse, both things he was experiencing. While Hermione went to books for things like school or just random information, it makes sense for Harry to turn to them for different reasons.
Third, surrounding second-year Hermione convinced Harry to convert some of his Galleons into Pounds. They mention in Deathly Hallows Harry had no Muggle money, so it makes sense that Harry and Hermione would think to get him some. (Also, the summer before Fourth Year is when Harry started smoking and would use some of his converted money to buy cigarettes.
Fourth Year is when the changes completely start. Like I said earlier, that's when the smoking begins. Also, I think that's around the time the self-harm started. I don't think he would cut that early, but he would scratch himself. Also, as a Ronarry shipper, I think that's when their crushes would develop.
Fifth Year is when the most changes would occur. That's when he would start to cut. The rest of the beginning is in the last part, so read that if you want to catch up. At the end of Fifth Year (this is a Sirius Lives AU), when Harry learns that Dumbledore isn't sure of his mortality, he tries to test it out by a suicide attempt. That summer, Sirius forces Dumbledore to host a meeting with Petunia, and when he discovers how bad she is, he goes against Dumbledore's wishes and takes Harry.
Non-chronologically, I also think that Harry was a lot more magically powerful than was let on and that he didn't know before Sirius because he wasn't cared for by someone who could help him.
So far, this is just a loose summary, but I'm planning to write more soon, and this is just me laying out the groundwork for those works.