Four young children to include

I have two nephews (10 and 5) and similarly aged "nieces." I'd like to include them all in my wedding.


I was planning on my doggo being the ring bearer, but I'm sure my oldest nephew would love to do that. Maybe he could walk her down the aisle and untie the ring from around her neck pillow?
I was originally thinking my youngest nephew could be a page boy, but I decided that I would prefer my train to drag behind me as I walk. He'd probably love to be a flower boy, BUT
I already asked the two girls to be flower girls.

Special note: The oldest girl is one of my bridesmaid's daughters, and while my sister is the MOH, this bridesmaid has been the acting MOH without even being asked. I know for sure that the oldest girl would be *thrilled* if I "upgraded" her to a junior bridesmaid, but I don't even know what that would mean. She'd be invisible standing behind the adults.
Any suggestions? No criticism, please 🙏