Will the speedrun with the custom sounds be accepted?

yes

That is, these heartbreaking sounds is allowed? just to clarify And is it allowed to change the title of chapters as at the end of the video? (Sorry for my English,i from Russia,that`s why i bad speak English) P.S. for ScriptedSnark да это твоё видео из дискорда фрифунчисетра

yes, they're allowed. WR run also had a sound package

Okay, but at the expense of changing the title of the chapters. In the video not Unforeseen Consequences, it was Telega polushilas

its allowed

And the last question) Are modified models also allowed?