The answers are below:

We get our own skin for the 5k? 
You get same structure but with ew colours, logo and design elements.

How much money do we need to run the operation? Are there laws for betting with crypto?
We are platform developers. For 5k we can sell what we have or add more features/gateways for agreed price.

Can we add fiat currency?
You would need to integrate providers or we can do it.