1) I think it basically does this if you just don't mint coins. How about some form of noble, that keeps track of each dwarfs income, and expenses, and then just manages a massive horde of coins, which eventually would only be used, when your fort traded with outside nations.
2) I guess I agree, or I just can't think of any problems with that, or anything to add.
3) Sure sounds good, I want guilds, they make me happy.
4) This is probably how it's going to go. I strongly support single temple, as I've stated else where, it makes sense to me, that while there are many Gods in dwarf fort, they could all still be part of the same pantheon. Guilds, could probably be an advancement of the manager. Starts with manager, eventually becomes a group of dwarfs, probably divided up among, woodworking, stoneworking, hunting/related, farming, fishing, metal smithing, crafting(and maybe jewelry), and engineering. We already have nobles to manage the healthcare system, and we used to and still do in ways, have ones to manage the military, so I kind of expect it to work like chief medical dwarf/manager. This is what makes sense to me, and becoming 8-10 dwarfs, depending how they format it, which is not more then a military squad, which is what the captain of the guard gets. I think, 30 dwarfs in a fort of 150-200 is not to much of a strain, considering most people can't find use for more then 80 dwarfs.
5) Don't hold me to this, but I thought something similar, to this is actually coming.
6) How about adding in foreign labour? Sure your dwarf can't make arrows, but the human carpenter you just hired sure can make them fast. Also just adding any form of foreign bought labour would add a lot to economy. Hire mercenary's, guards, craftsmen, etc.
Some very good ideas.