Be careful not to get Loctite on anything plastic. Plastic and loctite don’t play well together.
Is that complaint breathability/sweat? if so I really love my stealth gear vent core holsters.
Nope, but you've gotta make sure it's not worn in a way that it can get into the trigger guard. Some designs allow for worn leather to bend in to the trigger guard instead of staying open. Leather is extremely comfortable though. It's good to regularly inspect all gear you trust your life to.
I've always liked the leather/kydex hybrids.