I just got married 3 weeks ago, so I know what you wil be going through. Because my daughter is SO shy, we decided to let her be the flowergirl and walk down the isle with my sister, but we did not include her as part of the actual ceremony. I knew if she had everyone's attention, even with me and my husband as part of it, she would be most likely to hide behind me. She is only 3.5 though. As my husband said when we discussed it, at her age it was easier to have the ceremony just for us because she still has not fully comprehended what the wedding meant. If she had been older, maybe 5+ I believe she would have had a more active role.
I know this may not give you ideas, but I just wanted to let you know how we handled it.
GL and congrats!!!