Of course! Just please make sure you RSVP with your total amount of guests coming and let the Bride or Groom know in advance!
Yes they are, we just hope that they are looked after. There isn't a whole lot for them to do or be entertained with, so if a babysitter is available we would appreciate it if they stayed at home, especially the real little ones.
Feel free to dress as you please as this is a Semi-Formal wedding. Sundays best, Suit and tie, a dress, or a nice shirt/blouse with some slacks, it is totally up to you.