Types of characters:
Simple citizens with a social role/purpose (as seems to be designed and planned).
Factions:
Faction scores would open/close dialog options (as would Intelligence and Charisma). No idea what factions towards monsters represent and would be used for.
Powerful character abilities:
To always be able to feel challenged or threatened.
Setting as an imposition on your ability to generate a character:
No.
Game's mechanics to reward RP consistency, well made and popular characters:
It is impossible to judge consistency. For popularity (although I don't care much about the subject), you could add a Fame stat and have GMs give fame points once in a while, after public events. As an example, I wouldn't know who won a big tournament without reading it on a forum; if I can see some fame points, I may want to ask questions in game.
One thing I've always expected to see is a town crier, a NPC that you'd feed with news to shout and some dialogs about some of them. That NPC could be fed with infos about player characters who have achieved something.
Do you enjoy maximum levels / caps ?
No. I wouldn't mind caps if they were impossible to reach, though. What's more, top crafters shouldn't be the same; some should be able to do things others can't.
What area of development do you find the most important, why?
Balance.
Although a great deal of game is available, none of it can be properly judged. improved, extended, until at least part of it is properly settled.
What do you think the team should do to get more people?
Explain clearly and in details, somewhere, what the tasks of a dev are, how much time they spend per week or month, how long a dev can sign for, what tools they'll need to master, what kind of deadlines to expect, that sort of things...
Also, see if you can offer tasks instead of positions. Use temps when you can. Skilled and experienced people may have little time to give, yet this time may be worth something to the team.
To keep developers motivated to deliver:
Test, report, keep making features requests or wishes. And bounce when new features are announced.