Whitch Capulet servant fought Abraham?
This is from Act I, Scene 1 in the play. It does not say explicitly, but it seems clear from what is said that Gregory is going to fight. However, it is likely that Sampson fights as well.
We can see part of the answer from what Sampson says. Abraham says "you lie" and the Sampson tells them that they need to draw their swords if they are men. And he tells Gregory to remember his "swashing blow." So clearly Gregory is going to fight.
But then the stage directions say "they fight." That could mean that all of them participate in the fight. It seems unlikely that Sampson would not participate. So I think they all fight.
Yes. They all fight. This is clear when the Prince arrives and decries the edict that the next time this happens it will be punishable by death. For such a harsh punishment, you have to imagine it was not a well orchestrated, graceful, nor polite fencing match (as so often seen on stage). This was a destructive brawl.