K.C.
When I was confirmed, it was explained this way ... baptism is your parents and godparents taking ownership of your religious upbringing, thus during the Baptismal Covenant they say they will do things "with God's help" and parents pick the sponsors. Confirmation is when you are now responsible for ownership of your religious upbringing, so YOU pick the sponsor. My brother and I both picked close family friends. I would talk with your kids about who they would like to support them ... some questions they could think about are:
Who would they feel comfortable asking for a ride to Church in case you or your DH aren't going?
Who would they feel comfortable talking with religion and any doubts they have with?
Who do they admire for the things they do in the community and look up to?
Hope this helps. Best wishes.