The cutie marks of the mane 6 has changed throughout the previous generations ([link]) There's no reason the cutie marks of secondary characters would guaranteed stay the same as in previous generations
and obviously I'm not saying scootaloo will have a RD cutiemark, it's a paper cut-out taped on her butt as a sign she's a huge RD fan
I think they'll be different actually. Even the cutie marks of the mane 6 have changed since the previous generations, so why wouldn't the CMC's have other CM's as well? ^u^ Besides, a butterfly doesn't fit Scoot at all
My mind says "Once a CMC, Always a CMC". It emans, even with their CM, they will be the same, because their bonds are even stronger than a CM. Stronger than logic. Stronger than everything in Ponyville!... which explains why they end up causing chaos when left by their own.