Hi!
1 and 2 : No news tools i think.... I use a very simple tool, Notepad ++, it's perfect for no Dev person x)
3 : Test the mod tools on Fallout 2 game, I think it's similar. But hard way ^^
4 : I don't know, so high level for me x)
5 : No the engine is very simple, your PC can run a big map i think
6 : Don't delete, because the engine need the old stuff (or mod the engine but very difficult way?)
7 : Completely! The graphic engine is very particular, to mod the Fallout 2 colors'system for example it's difficult. The Dev who made new item or graphic elements are very good!