In a 240L tank - ypucould go for bigger species (make sure smaller fish wont be scoffed)
2 BNs would be fine - i wouldnt advise any more than two - you cant guarnatee male/female when they are young - if you get two - and end up with a pair then great - if you end up with 2 females then thats fine as too are two males (just about) but two female and one male - well - he wont be happy - as the females push the males aropund at breeding time (aint that always the way
) and I seriouslt think he'd get stressed.
5 banded barbs are nice - my LFS regularly has them - although I think tiger barbs have more character (in a tank of 240L you can have a shoal and they will keep any agro to their own kind - I have a shoal of 10 and they are np bother at all) - really - the world is your oyster right now
You Could even keep angelfsih in the 240
You could use the 90liter for Rams or kribs - they will breed in there but not like flies (like the shellies apparantly do)
Anyway - lots of options out their