Title is question. Thanks!
yes.
yes! in fact all of the manufacturers with the exeption of apple and certain tablets have all started using this universal style micro usb that can also charge from any device that has a usb output as well like a computer, game system, car stereo, etc
NO. The charger will work and charges the battery very quickly. But from what I'm told, there are differences (I've looked and they are subtle.) Supposedly you may eventually fry your phone with the Motorola chargers even though it works. I'd double check.
You should be fine with another cell phone charger as the differences are going to be minor. The stock Thunderbolt charger is 5V@1A and the droid x is 5.1V@850mA.