All i would suggest is swapping the clown loach for a couple dwarf chain loaches, clown loachs get big and could get stunted in that tank, other than that, your tank looks great
How many discus could be kept in a 250L planted tank?
I would be getting themat around 2cm and growing them on to about 6-8cm(?) in a BB tank first.
Tankmates would be Cardinal tetras pencilfish and a few corys
Just throwing around ideas here.