Regarding the script editor: you can try to upload it to the game folder bink2w32.dll (x86) from this link: https://github.com/ThirteenAG/Ultimate-ASI-Loader/releases

Roofs in the game can be turned off completely if you delete all bytes with the HEX editor in the static\imagelists\roofs.dat file

I don't know how to remove the veil in the dungeons yet, but I think it's possible.

I don't have much free time right now, so the editor hasn't been updated for a long time, but one day I'll do it.