Feats are fine, with Defensive Roll specifically stacking
. I believe that Steve also OKed the Tough feat from Warriors and Warlocks. But yes, the idea is that Superman doesn't benefit from wearing a bullet-proof vest. And yes, that means that feats such as Throwing Mastery and Attack Specialization also apply to equipment, even if they're power-based. Oh, and Constitution, even Enhanced Constitution, stacks.
As for the Laser Sight, that's not considered to be a power either. And yeah, a +2 makes as much sense or more sense than the +1. Personally, I tend to allow Equipment to have up to 1 rank of Improved Critical or Accurate to model the idea that you have a particularly keen or accurate weapon, but I'm a bit loathe to go past that. After all, it is supposed to be mundane "off the rack" equipment.