Minimum Rebellion forces needed to take the Trek Galaxy?

[The Romulan Republic]

I've seen a lot of old threads on how many Imperial ships it would take to take control of the Alpha Quadrant, or the Federation, or the Galaxy, but what about the Rebellion? Keeping in mind that the Rebellion would probably not be able to use such tactics as a BDZ, mass enslavement, or planetary destruction for political reasons(correct me if I'm wrong).

So here's the situation: The Rebellion detects a wormhole leading to another galaxy, and for whatever reason decide to send a task force through. The mission: to make contact with the locals and ally with as many of them as possible. Super weapons, genocide, slavery, and indiscriminant bombardment are disallowed for political reasons.

However, the wormhole is unstable. Once you go through, it will close/jump into intergalactic space for the next five years. Can the Rebellion (pre-Endor) field a force capable of pulling this off, and if you were in command, what forces would you use? What tactics and strategies would be most effective?

Also, let's say that the wormhole will reopen in 5 years in Imperial space. Can the rebels upgrade the Trek factions enough to give them a shot in guerilla warfare?

This is my attempt at a fairly original vs senario. If its been done to death, I apologise. I'll post my own opinions once others have had a chance to respond.

[chr335]

I can't really see them needed too many ships as they are on a diplomatic mission. A small task force of maybe 3 or so Assault frigates with a couple of light carriers, such as Nebulan B escort frigates, escorting a corvette with the diplomat and his/her/its team.

[Ghost Rider]

Jesus fucking...never mind. The level of firepower are on par. The Alliance forces are smaller then the Empire, but would laugh at the Federation, and fuck most of the convential combined forces of the ST universe. Locking, because this is a force substituition of instead of using people in grey outfits, to using people in white/beige outfits.