Now is the scary time. All this planning and now you have to really do something. Have you any idea of what fish you want? I would suggest that you think of all the fish you would like in the tank at the end (make sure you consult your daughter). In fact my daughter is next to me making sure I type correctly
Once you have worked that out; you can see if they fit in your tank (quantity and size) and also see is they fit together. I have had my 1st tank now for 4 years (now my daughter), and my 'new' tank is 12 months old. When I started to think what fish I wanted; I have a list of about 15-20. After a little research and planning I came up with my stock plan. And all is good.
Saying this, I still would go out and 'find nemo'.
I am no expert; however, I would say that to get 2 of the same species and not to mix the clowns, I have seen it done well with a largish tank. See what others think.
Good Luck - Good Planning