Most of those can work together well enough, except for "can fly" and "somewhat bulky". The bigger your gargoyles are, the more fragile they're likely to be.
Powered flight is hard. It is energetically expensive, and as a result requires strong tradeoffs to make the amount of energy required for a particular creature to fly low enough to be attainable. In real-world flying creatures that has usually meant shedding mass in the body (like birds' bones being hollow, using uric acid rather than urea to excrete waste nitrogen to avoid needing lots of water to dissolve it in, and lots of others).
Those tradeoffs don't work so well with bulk. Bulk is heavy and usually not very aerodynamic, meaning it would take more power to get into and stay in the air. More power generally means more muscle, and muscle is heavy, so it adds more bulk, requiring more power, and so on.
That may not ruin the creatures for your story. If they only need pseudo-flight (basically gliding), or only need to be in the air for short periods and don't need to get far above where they started, then the bulk might work out. But if you want them to soar through the skies, or fly from the ground to the top of a Gothic cathedral, then the bulk is going to be really hard to work around.
The rest of the features don't seem like they would be impossible, or even unusual.
The question of "what evolutionary pressures would lead to them" is really, really, really broad. The answer would be "any that lead to that outcome", which probably isn't very satisfying.
You could start with a Nyctalus lasiopterus, and then simply have them get bigger, grow longer tails, and so on, but looking for an evolutionary reason for each specific feature is probably not worth doing. "Mate selection" is fair enough as an answer that can lead to profound changes over long periods of time, especially when you don't have to rely on unpredictable factors to actually produce the changes you want.
Figuring out what ecological niche the gargoyles exist in might be helpful if you don't want to handwave away all of the details, but there is no real limit to the possibilities that can be imagined when we're not constrained by actual events.