If specters/equipment can be used, they can be really helpful too (wiki doesn’t say mention if gear wheel is disabled). Something like a wisp specter provides some CC and some healing to the objective and will last the full 10 rounds. A railjack specter will probably despawn before the end of the mission but they don’t cost anything to craft, and can be helpful with trying to keep the Defense objective alive.

As for frames, Wisp, Xaku, Octavia, Hildryn or Nekros (Ivara should be fine for survival and comes with a looting ability for life support so might be worth it to run there with melee/weapons that are silent by default like the Baza) would probably be my choices for frames that should do okay without mods. Grab any augments you like because they still function in the Grendel missions.

If power cells are really an issue in excavation, just spawn a new excavator and let the old one die assuming the mission is total cryotic and not n-excavators completed. Preferably though, you would be playing Nekros here for the extra canister drops.