Sure ... they can even be used to amplify electronic keyboards, too.
bass amps are not able to handle the high frequency that a guitar puts out. yes it will work for a little while but I would not...
Its really personal preference. Just get out there and try as many different brands as you can and then choose for yourself. If you want more of an answer, I know that Ashdown amps have a nice bassy...
Of course. You will not get that "in your face" low end sound, and if you crank up the volume, you can blow a speaker out, but if you're sensible about it, it should work fine.