Yes, it's possible for a female to carry only a few eggs. Some years ago, I ordered a group of YKK's. After a week or so, I had two extra shrimp that I don't recall having when I acclimated them into the tank... and that was on top of 2 extra I found that I wasn't supposed to have! I don't recall the exact amount that was shipped, but it was something like 15 shipped, 17 arrived, then I had 19.
If the parameters aren't right or there's not enough biofilm, the offspring could parish... or they just might be hiding.
And neos are born "colorless". (might not be colorless under a microscope though!)