* Mechanically how will spells be handled?
-> As in other games you will have your spells in a menu to activate them, aim them at someone or something and cast them, taking a certain amount of time. You will see mages casting if you can see them doing it. Otherwise if you are able to see into the astral, you will get ideas about who is geared up in magic trinkets or has magical abilities.
* Will Drain be used? And if so how? How will we get rid of Drain?
YSes and not sure to the last two

* How much variety will we have in the spell lists? All the spells in the books? Just SR4A? Street Magic?
-> we haven't begun to sort through spells with an eye to "can be done" and "can't be done" yet.
Please don't use a "Tier Tree" of magic specialization ala WoW talent tree or that type.
-> we will stick pretty much to the way spells are gained in SR, though again, we haven't tackled that yet
(I know you couldn't possibly put it in from the start but maybe later, a tool to make custom spells?)
-> VERY complex issues, but noted.
* And the big one I wanted clarification on, Spirits. Will they Be in the game? From the start? That's
a sizable portion of a casters arsenal there. Are they going to be like the hireable "Mercs"? or will they
be separate from the party size limit?
-> honestly and not to put spirits down, they kinda handle like drones- you summon them, bind them and use them (and perhaps upgrade them?). so yes, they should be in in some way
* I saw you said Initiation won't be in the game from start. Will it be added in later? If not, is there
another path you are planning for power progression for casters?
(Also corollary to this, and to derail the thought train here, if casters don't have Initiation will
Technomancers have submersions? For that matter will there even
Be Technos in the game?)
-< technos-> as mentioned we aren't sure about them and will deiced once we have the basic types running. Initiation/power progression...again we haven't really pinned that down yet
* Will there be a difference mechanically in Mages and Shamans like in the past versions of the game?
and alas, not sure. perhaps more a question of differenmt arsenal and casting times etc.