@Nadi - one rule of thumb is the younger the plant the less it will like transplanting or being disturbed.
Any idea what these are? Are they from seeds that fell from local trees or would they have come in from compost or potting mix?
I have transplanted oak, maple, and a few other midwest US type trees. With only the first two leafs on it you're more likely to kill it than not.
Few pointers or just thoughts:
- Disturb the roots as a little as possible. Transplant a large ball or dirt with the seedling in it and do so with the soil as stable and unmoving as possible.
- Don't let the new roots and transplant dry out at all. Water it it well and keep it watered but not soaked.
- Don't put the new transplant in full sun - you'll bake it to death.
I'd let them grow larger then transplant from that pot to another but it looks like you have them in with cactus things. I expect the tree will want far wetter conditions than the cactus will want. But, I'm a confirmed cactus killer.