Guitar or Piano for ceremony?

Definitely don't ask your family to work.

Don't make family work on your wedding day, regardless of their profession/professional status.

I think either would be fine, but don't make your family work on the day.

Thanks guys! I hadnt thought about it that way! I will definitely not ask my brother!!!

On one side of my family of 25 people, over half of them are professional musicians and/or ministers. (No exaggeration). My uncle (a professional minister and the minister of the church FH and I are a part of) is marrying us. I will have a couple of family members (who are professional musicians) do a song each in the actual ceremony. I will pay all of them (officiant and musicians). This is my way of incorporating people who are important to me in the wedding without having a ton of ushers, BP members, etc. However my dad is both an officiant and a pro musician and he is doing neither at the wedding. His job is to be my dad and walk me down the aisle.

My point is that each situation is different. Don't make your family members or friends work (as in being a day of coordinator, the caterer, the hair or MUA, the DJ or something major like that.) They need to enjoy the day with you and not stress! But asking them to do one thing, like play a song in the ceremony, do a reading, be an usher, pass out programs, etc, is ok as those things tend to enhance the enjoyment for people and make them feel included instead of being a stressful day of work.

I see no problem with asking your brother to play a song for you. It's not different than him doing a reading or ushering. You're not asking him to do the whole wedding, just a few minutes. Also, I think both songs would be more beautiful with an acoustic guitar especially the Beach Boys.