There was someone who tried to ask a long list of detailed formula questions, and Toady basically said that one of these per FotF response session was enough (too much time to go back and investigate), but that's the only time I've seen Toady say anything about the number of questions, so straightforward ones shouldn't be a problem (but I'd probably limit it to one maximum post per FotF response session at the most anyway).
For the scenario, there will be some kind of sliders controlling abundance and power of magic (although the exact set of sliders haven't been decided on). There will also be various RAW file mechanisms for controlling aspects of the world, and as far as I understand that would be usable to determine the spheres of magic present and I would guess also whether the kinds of magic (magic items, rituals, ...). Thus, your scenario doesn't seem impossible.
Once magic is in but before the economy gets overhauled, it would probably be possible to run a fortress based on selling magic items. Once economy gets back in, there'd probably be some kind of supply and demand involved, so if everyone can make magic items easily, they wouldn't sell for much. If, however, your fortress somehow was the center of magic development and most people didn't know anything about magic, you'd probably be able to churn out easy to make magic items for a pretty profit.
All of that is speculation based on what's been said, though, and magic development is quite some way off yet.
(And, Shonai_Dweller, I think some word incorrection SW has attacked your "Threetoe").