Ya i too am blown away. Your tank your choice, but you are asking for trouble.
Your mandrine will starve unless you are feeding it pods weekly (by buying some pods). I assume your BTA isn't extremely healthy because i've only had mine for 3 months, and it has grown from the size of my fist to about a dinner plate size (8 or so inches from one side to the other side of its head). So even if it is healthy i'm sure eventually it is going to eat your mandarin.
As for the anemone, aside from 10 gallons being too small for an anemone, the only ones you could probably get are tube anemones, which will not host clowns.