I am not close (haven't even met one of them) with my two young cousins and my fiance isn't close with his young cousins either. We live on the other side of the country from them.
I grew up babysitting two sets of families and am very close with both sets of parents and their kids. The older girls will be 12 at the time of the wedding and I'd like to include them in some way. From the other family the kids will be 6 and 4 and I'm contemplating asking them to be flower girl and ring bearer unless the parents want a day w/o the kids. Is it rude to ask these children outside the family to be a part of the wedding and not ask related cousins??