Will these fish work together?

A 55 gal. tank should be able to accommodate those fish just fine. All of the fish you list are pretty peaceful so you shouldn't have to worry about aggression. I would wait until the tank is well cycled before adding rummy nose tetras...in my experience they are very particular about their pH (the red on their nose will fade away if the pH is too high or too low, so they make good pH monitors at a glance). Also, guppies are still schooling fish and I don't like to keep less than 4 or *maybe* 3 of a schooling species because I feel it stresses them so I would consider either leaving out the guppies or getting at least 4 depending on how crowded your tank is. Also, you don't say whether or not your tank is planted...planted tanks can handle a slightly heavier fish load than an unplanted tank.