I would say it is overkill. All I have in a 14g is a juvenile maroon clown, a baby yellow watchmen, and a juvenile firefish. I think the rule of thumb is 5 gallons per every inch of fish. As its already been said, you will have to get rid of fish as they get older.
Also, two clowns will become VERY territorial, more so that one clown. Your other fish might not get to do anything but stay hidden all day. My maroon tries to scare off my yellow goby but he doesn't put up with that and stands his ground...but then again he isn't out and about all the time like he was before I got the maroon. The firefish only comes out for feedings. So, I would say no.