- answering rules questions
We can all do this. Seriously. Most of us have been around for a time. Still, from time to time, DM's final word may be required. You made the rules. No one can replace you there. Sorry.
- interactive actions; replying to IC emails/posts regarding wars, adventures and diplomacy
This is a bit more tricky. Not a good idea to let a player or his enemy roleplay his vassal, unless the vassal is charmed or dominated or something like that. You could create a thread here on the forums where you would request assistance in roleplaying NPCs. We could then apply whenever we want to help.
For example, imagine Tristan Bellamie has a diplomatic misunderstanding with his cousin, who is an NPC, and you need someone to help roleplaying the cousin. Assume I'm playing Aerenwe. I wouldn't even apply to help because I could get some information my character is not supposed to know. Someone playing far in the north would probably be ok, though.
- processing some DOs
I doubt this can be done by a player. You get to know someone's darkest secrets by looking at his DO. I'd be happy to build a web app for DOs if you want me to, though. Would be fun.
- giving me input/editorial aid with the SR
If you want to put SRs online, I can do nice stuff with html and css. Editing docs and pdfs is not my thing. Do you also need us to remind you about events in our domain we think should make it to SR? We can all do that. Also, it would be mighty nice if someone could make the SR looks like a newspaper, like what we had in those older PBeMs in the previous decade and... well... in the previous century, damn I'm old