The Clowns will eventually need a bigger tank, however they are pretty slow growers so assuming they are juvi right now no problems.
Bolivian rams should be fine with tiger barbs, ensure you have a large shoal of tigers though at least 8, this diverts there attention away from other fish as they are busy fighting amongst themselves, great fish I love tiger barbs.
You could have a nice shoal of TB, 5 clown loaches (to be rehomed or upgraded in the future) and if your looking for a pair of bolivians, get 6/7 to start with and wait for them to pair up, then return the remaining ones, or perhaps keep two pairs in a 300L.
