Hi and welcome. Looks like you've got answers to two out of three of your mystery plants.
The second picture is out of focus, but even if it were better, not sure we can tell what that is from the one big old leaf. You might have to grow it for another few weeks until you have some good fresh leaves to show us. That leaf is really in rough shape, burnt at the edges etc.
It looks like it might be a Begonia cutting that someone has rooted but it hasn't really got going yet. Keep it warm but not too wet, and in good light but no direct sun. Post another picture as soon as you have some new leaves, please! Our curiosity is piqued.