My static doubles partner is a oli/pika main so I know a lot about this team.
GaW should be reacting to what olimar does, and trying to keep the perfect distance away from him. If you're too close you both can accidentally kill each other, and if you're too far the olimar is going to get double teamed.
I find that vs a double MK team, the MKs usually always double team the olimar, because he's a lot easier to juggle and gimp. It's now your job to punish the MK players effectively as possible, and prevent oli from dying. The GaW should think of himself as an MK, but with less pressure options but high kill power.
A shared trait both of you have is the low kill power, so you should both be wanting to punish them for hitting your teammate with a beefy smash attack, or some sort of high damaging combo (GaW has nair to nair, oli has grab combos etc.)