I do not dim these bulbs, however dimmable LEDs will dim if you use a LED compatible wall switch (the driver will eliminate the hum from the bulb)
If your socket is PLASTIC, a larger incandescent wattage will present a fire hazard. Porcelain or metal clade sockets are more money but are far safer. LED bulbs do not create as much heat so you can go larger in what you have.
None of these other answers are correct. Wattage, fit, 'it seems to work', etc do not dictate whether an LED bulb can be used in an enclosed fixture. LED bulbs produce heat, and need a way to vent that heat in order to remain within the advertised lifespan. Most LED bulbs require open air to do this, and are therefore not 'rated' for enclosed fixtures. If you used a open-air rated bulb in an enclosed fixture, it will work - just for a shorter period than it's stated life span. This particular bulb is rated for enclosed fixtures, as stated in the specifications above (that is most likely thanks to the strange shape, which is probably a form of heat spreader/sink.)
No, it will fail prematurely. Get the 60W equivalent for now until they come out with the 75W that can be used in enclosed spaces. Cree owns the patent on this technology.