Two (and Too) Noob Questions

Falcon.

My friend, use the Falcon with Cryo. Bring your best SMG with the HVB for bosses and big armor. You really won't need it much, many matches I just Falcon all the things.

Human Engineer - cast Overload. Fire Falcon shots into the mob while on CD. When CD concludes, cast Incinerate. Maybe a Cryo Explosion or two. Cast Overload again, get Fire Explosions and/or Cryo Explosions. They're Dead.

Cast your Suicide Drone constantly at sniping enemies, like Phantom, Nemesis, Marauder, or Geth Rocket Trooper. Geth Primes absolutely get incensed at the presence of your drone. It's damage is small but it attracts attention, which gives you a little room to breathe.