you should consider more tiger barbs than 2. If you don't have enough barbs for them to form a pecking order then they will be more agressive toward other fish. Tiger barbs may not be your best choice for a 10. The number needed to curb agression would pretty much fill your tank. Smaller tetras like neons, gold pristellas are good choices. Cory cats or otocinclus are good bottom feeders. Maybe a dwarf gourami and possibly some platies or swordtails for color. Your daughter might like one of the pygmy puffers. I don't know much about them so i am a little hesitant about recommending them but they seem like something a kid would like. Just be careful it doesn't get sucked up your filter.