I can't answer all of your questions, but I'm a retired gunsmith who has spent a lot of years working on SAA's. Given what you're going to do with this revolver, I see no "need" to do anything at all.
A spring kit - Absolutely non-invasive modification that anyone can do and undo. If you do, just keep the original stuff. Spring kit will make thumbing the hammer back a little easier, and could improve trigger pull.
Trigger work - If there is an abundance of creep in the trigger, you may at some point want to address that; but it's more personal preference.
Forcing cone - Unless you need absolute nats-azz accuracy, this is a waste of time. If you cast your own bullets, and really want to milk out every last bit of accuracy, then perhaps. But I'll tell you, it costs me NOTHING to do forcing cones, and I don't bother to do it on my revolvers...but that's just me.
Grips - I have owned sambar stag in the past and while the look fantastic, I have yet to have a set that really felt "right" on the revolver. I have elephant ivory on one of my guns and if I had to do it all over, I would just buy some of the better quality synthetic ivory. The better synthetics actually look better, feel is even the same, and of course cost much less. My favorite grips for the SAA are the factory hard rubber; but that's just me.
Leading & jacketed bullets - I can remember a time when people would tell you that was a no-no. But after inspecting a bore with a borescope after shooting jacketed following lead; I say its the best way to clean out your bore. If you're really anal about it, you will still have some leading, but it will be FAR less, and way easier to remove.
As for full detail cleaning - Taking the gun apart on a regular basis will cause its own "wear"; so just be aware of that.
I'm jealous...I'm SAA-less at the moment, and I wish I had your problems.