Cherry barb and tetra question.?

I have 3 cherry barbs with guppies 3 female bettas and 4 panda platties. My 3 barbs aren't schooling together they kindofnstay Way from eAchothe! I thought they were a schooling fish?! Is it cuz I don't have enough? I only got three cuz that's all the store had. And I am going to get a schhool of tetras. 4 neon tetras, 4 black neon tetras, and maybe 4 golden tetras. That's good right? I no they like six but my old group of 4 neons and 3 goldenseal swam together all the time. If your good and doing taxing, if u want u can figure out the life of each fish and how much the school of 4 would cost plus tax.'thanks