How do I administer commishion

So I have made a basic store at shopjust.org/chotika

Now I need a few things to make that viable.

1.
Paying. Paypal will be the only option out the gate, but I need to set up comissions, so that when a customer buys, x% is sent to shopjust,org and the rest is sent to Chotika.

I also want the commision to be calculated before transport.

Where do I set up this?

2. For some shops, there is gonna be a 3-way dividend (3 receipients) Where do I set that up?

3. I would like the customer to choose which currency to pay in. Where do I set up that?

4. I would like the customer to be able to view the site in different languages?
How do I set up that?

5. I would like the customer to be able to check in with Facebook. How to set up that?

6. When all this is done, how do I make this shop the template for new shops?

Best

Gunleik Groven