The reality is that this game had consistently been the most popular game for over a decade now. So practically any exploit that could be in the code can and has been found. The source code is just a cool novelty to see how this game was developed at this point.
Yeah, but probably not on GP, due to the copyright... so there will be people doing cash grab asset swaps with ad for every time you move a meter, and obviously malware creators on the internet
Yes, they can, but it doesn't mean they should, unless you wanna buy a new phone every few months, I'd know because I used to play Genshin on my phone.