Ok, I can get some clues from the leaves of some. For example, How many Potato Leave you had in that mix tray and how many RL. If one tray is all the same there will either all RL or PL.

Silvery Fir Tree, You can tell it from a mile. I happened to to have just one seedling (18 days old) myself. I can easily tel which one it is without looking into the tag. It has sharp teethed small lobes.

Not sure on the leaves of the other kinds, like I said, I'm not too worked up about those, Ill find out which is which by the time the season ends haha. Good to know it will be easy to tell the SFT though, since that's the only one not going in the ground.