Any easy way to cheese the Quaid GQ?
Which part are you having trouble with? It's been a while since I've done it, but here are some tips for the bosses:
Graham: If you have Tilith or Mikael, or a friend of either, both are strong leaders for the encounter. They negate status, give some tankiness, bc fill, and both have a complete invulnerability UBB, which is great to cheat the 50% and 1% mega nukes.
Shusui: Easiest boss, just be sure to kill him in less than 14 turns (required for gold medal).
Plant boss: Another boss where a status immunity leaderskill is a huge help. You want a healing mitigator on this team (Krantz, Elimo, etc). Put two very tanky units in the top row, and put your healing mitigator on the bottom row (you can't move the guest units). Every few turns the boss does a huge single nuke on someone in the top row, so guard them (or if using omnis, they can likely facetank it, unsure). Don't push him over a threshold nuke on the same turn he's doing his single nuke on the top row.
Melord: Arrange spheres so one unit on your team has low max hp, but super tankiness, especially while guarding. Spheres like Demon Silk and Adaptation Jewel are superb for this. Have your lowest health unit guard every round for the whole fight. Each turn, Melord does a nuke on the lowest health unit, and it ramps up every round until it finally kills the unit, which resets the damage to base. With +guard spheres, it should take 10-14 turns before the unit actually dies. When they do, just revive them and make them guard tank again. You should be able to finish Melord before he kills your guard sponge a second time. Be aware that he will wipe your team when he hits 0%, then angel idol to 5% health. Have team 2 finish him off.