Weddingbee boards

Ok, a little backstory. I have 4 nephews, and 2 nieces. Two of those nephews, and a niece live about 10 hours away. The rest live in my same city. My oldest nephew here is 19, my niece is 15 and my other nephew is 5. FI on the otheR hand only has one nephew, who's 2 and a niece on the way. He made it non-negotiable that his only nephew be our ring bearer. I'd prefer not to have one at all, I didn't want to choose between all the boys in our family. He HAS to have a flower girl, according to FI. My youngest niece is only 1. I suggested his nephew pull her in a wagon, he hated that. He wants my first cousins little girl, whom I never see, to do it. I'm having a hard time justifying that, when I have two nieces......sorry this is getting long winded! Anyways, I'm thinking about asking my 15 y/o niece to be junior bridesmaid/flower girl......I never really liked the idea of a junior bridesmaids, but I think this might be our only option. And I really wanted her to have a bigger part than guest book girl. What do you guys think? Would that look ok, having her walk down the aisle with the little guy? Any other options?

I think we'll be doing the same thing with my fiance's 15 year old cousin - she's too old to be simply a flower girl so my mom suggested a junior bridesmaid. I'd rather not deal with having a junior bridesmaid since I don't know any of the etiquette involved it. My other bridesmaids/matrons are in their 30's and having a 15 yo tagging along will be awkward, but she's a peach and she really wants to be in the wedding, so I figure we'll just work it out somehow. I think our ringbearer will be our 110 lb. dog also (if we can convince the church to allow it) so to compound matters, her date will be a huge hound. I think she's got a sense of humor at least!