1 - If the question is about Zoda's joining, it's already happened. If you're asking about the FwM RP itself compared to the FiM RP, I don't think there really is a correlation between the two timelines. It could just as easily be ten years ahead as ten years behind from my perception.
2 - I do not see any reason why she can't. That would likely be the fourth General though.
The current lineup of Dark Forces ranking officials to my knowledge. If the listed individual is 'Unknown', that means the slot is unclaimed.
Leader - John Flitwisp (Identity Secret)
Second in Command 1 - Unknown
Second in Command 2 - Unknown
General 1 - Hullaxburom (Likely to be 'replaced')
General 2 - <Soft Serve's idea>
General 3 - Unknown (Lix is welcome to this one)
General 4 - Zoda
Major 1a - Unknown
Major 1b - Unknown
Major 2a - Unknown
Major 2b - Unknown
Major 3a - Unknown
Major 3b - Unknown
Major 4a - Unknown
Major 4b - Unknown