The baby looks like a Bumblebee platy. Maybe the mom was in a mixed tank of platies and got pregnate by a Bumblebee Platy. My bumblebee platy was in a mixed sex tank and has 5 different colors in the fry.
1. Blk/Yellow bumblebee pattern
3. Blk/yellow some red
5. Blk with some white really cute like a Orca whale. I have 1 of these that I plan on keeping.
I'm going for the bumblebee pattern with the blk. mask face, I posted 2 pics of my bumblebee platies and 1 pic of the blk and white baby platy mostly black with a little bit of white.I call it my Ocra baby.
I like your pictures of the platies. They are really cute.You are smart to only keep a few. I rehome the ones that don't fit my pattern on craigslist or the LFS.