Suspicious GAC Fights, what do you think

Your opponent lost two units, so it was not clean and I'd hardly call it suspicious. Not sure why you think g12 is equivalent to g6. Traya gains bonus protection when Sith are debuffed, she can give Protection Up to someone else when using Isolate. And like someone said, Traya lead will make them damage themselves; that's percent health based, so it's proportional damage, and higher relics make no difference. In fact, if relics are adding more max health relative to max protection, higher relics might mean they kill themselves faster. A g12 can easily take out an r7 in the red. You can argue that BAM might throw up some damage immunity, but the other team only needs to survive until annihilate is ready (which goes through damage immunity). Remember that Nihilus might have protection up to help him do that. Once that first annihilate goes off, Nihilus adds that fancy relic character's health to his own. I see nothing suspicious about this, as he's the only unit surviving.

The Executor counter is weird, but again, given the banners, I'd say it was just fortunate RNG. Falcon is probably there to help ensure targeting of vulture droids (though having SF up front seems counter intuitive to this). So I can't vouch for this particular comp, but again, the bad banners helps assuage suspicion.