Will 2 clownfish (already have), and 3 blue chromis fit in a 16g bowfront?
Could work, though not optimal for a thriving condition.
I looked in to chromis my self as the gf liked them, i have a 32g rimless thing like a cube shape. After watching videos of them i decided even my tank would be too small as id want at least 6-7 to get the real effect of them shoaling up and down. Just my input though. The old 16g i had housed my 2clowns and a blue neon goby, that was it fish wise, with the smaller tanks i get most of my enjoyment out of the corals and inverts.
They should get along just fine. That's pretty cramped for 5 fish though. Usually I'm pretty generous about stocking advice but depending on how much rock you have, it can be a pretty sad environment for adult clowns.