Can you trade equipment between combat with multiple creatures?
The FAQ attempts to clarify this but the answer to the Q here is still not crystal clear even after the clarification=)


  Q: Exactly where, when, and what can investigators trade?
  
  A: Investigators may trade any time during the Movement Phase when they are in the same location, street area, or Other World area except during combat. They may trade before, during or after movement, which means trading does not end a move.


I would say "yes, there's a period of time in between combats you can trade" however.  I think it is pretty clear all the combats do not happen at the exact same time (and rather are sequential).  Without the FAQ, I would have said "no" because the word phase was not used (and it is other places "end of Mythos Phase") and would have guessed they meant actual movement rather than the Movement Phase.  However, the FAQ specifically says "Movement Phase" which I think makes this more clear.  While you are still fighting it's still the movement phase and being that it's not over you can trade as long as not in combat.

The other thing I looked for was a multi-monster combat example, to see if they used a word like "immediately" but there was no such example I saw in the FAQ or the Rules.  This might be an additional guider if you can find it.