If you have a couple of books you should be able to find out what species of tree you have, you will also see that the tree needs pruning now. There are links on here for identifying specie have a look. The seedlings may be ready for potting on, only you can tell that.
Why are your seedlings in a fridge? Are you trying to kill them? Get them outside.
The tree looks like a Zelcova, it need pruning hard but only you can decide what needs to be done.