Where should I put these tattoos?

Wow - these are great! I love the erfly fairy. She's beautiful, totally understand why you want that where you can see it all the time. I think that would be great on your wrist or forearm. The way she is sitting, it would look like she is resting on your hand. I think your ideas for the other ones are great. I am not into full back tattoo's, so I would agree with your thigh placement for the cross. But to each their own :) Hope this helps.