You are probably right about the white one, it may be the head and it is too young to tell. They grow quickly when young so a few weeks to a month will make all the difference. As you say it may end up being a swan, very apt if it is all white when it grows up!
I have seen multiple sources say they grow about 50% with each moult when very young, and I think this is probably about right, and they probably also moult more frequently as well, as they out grow the shell they are in so quickly?
It was like that before, it might, or it could be the brain or guts, may be as jayC said, time will tell. But just a few days, now you can see the white all over its tail stand out.
As you can see from both photo's, they are completely different, both same size. may be the white one is the ugly duckling from the rest, and grow to be a beautiful swan at the end.
So far I only spotted 5 crystal red babies including the white one at 2mm, but it's a jungle out there for them, there could be more, I haven't included the neo, I have about 6 babies, but not sure how they got there, may be it was already in the tank when I removed all the larger Neo, but didn't noticed them, they are about 6mm.
Does the white one look like it is starting to go red as JayC said it may, or is it my eyes/the photo?
The red one is a nice shade of red, was the mother a red wine or a crystal red, it looks a bit more red wine to me than crystal red? You said red bee!
How many babies have you seen so far?
Hopefully you are at the end of your spending spree? Though with setting up the tank in the near future, with new substrate and changing the water that is going into it you should probably get some water test kits, if you don't already have them? I imagine they can be got from any local aquarium place out there, but again, buying the full kit, Ammonia, Nitrite, Nitrate, Gh, Kh, Ph may be a bit costly when you get them all at the same time. You will get the TDS meter with the zerowater jug of coarse.