A big open room doesn't make a dance studio. Nor do hardwood floors. You need to have sprung wood floors if she is going to dance. Don't let her jump or do petite allegro unless you are going to invest in that. She'll get repetitive stress injuries like shin splints and knee pain. If she just wants a place to stretch and practice, it should be ok.

You definitely do not need mirrors on every wall. You need one set across from where you put the barre and maybe one directly in front if she is a ballet dancer.

Then again, some schools of thought take the mirrors completely away so that the dancers feel their placement instead of relying on the mirrors. The American dance festival covers all the mirrors for every class for example.

I recommend alva's for barres and accessories.

Right now those floors aren't going to do much. If I were you, I would not do the whole hardwood thing anyway and put down Marley floors. That's what every professional studio does nowadays anyway. Many dance specialty companies will make the sprung floor with the Marley on top that you can just stick on top of your existing floor.

I am a professional dancer and teacher and a director/purchaser for a large health club.