I think you should be fine. I would be more worried about having enough room for them Cory cats. They are heavy sand sifters, not alot of real estate there for them to sift thru.Unless you can have 6 julii cats, 6 bloodfin tetras and a betta in a 10 gallon without it being overstocked.
I would stay with the five. Stay on top of your maintenance, Cory's are little poop machines. All that sifting means a lot of scrounge eating/poop production.Ok so just stay at the 5 Juliis then?