you have to mark it as funds for long term stay in Wise when you send the money but it isn't guaranteed to work. If it isn't marked correctly in your bank book or statement then you can't use it anyway unless you get a foreign funds transfer certificate. There's a FAQ on Wise regarding this. The only way to guarantee an international transfer is to use swift
you can only get that 90 day Non-O visa inside Thailand without having the required funds in a Thai bank account is if your embassy will provide an income affidavit/certificate proving you have the requisite funds. And if they will still do that you don't need the money in a Thai account for an extension either
exactly. Turn up with everything and give it a go. I've never seen anyone saying they've been refused the conversion but then again I don't know if anyone has ever tried.
Your inheritance will have come from somewhere, get whoever paid it to you to write a letter stating the provenance. I'd also be prepared to show how you will be able to support yourself for the duration of the DTV 570k baht isn't going to keep you