Yes the odds of success would be much higher but as previously stated most of them grow at different rates with the clown loaches being the slowest growers so unless you buy large clowns they will end up as food
synodontis (depending on species) can get decently big and clean up unless your trying for a southamerican only vibe the. I'd suggest brochis splendors its basically a giant cory cat. In the end though there isn no fish that just eats **** the best cleanup crew is you×waterchanges+gravel vacuum
Look the honest thing to say is most of these fish don't, won't or can't live together. Not saying it couldn't work for a while or in a huge "tank" like thousands of gallons. In a 150 you are limited severely by many things before you even get into the nature of the animals in question.