Howdy Jeff,
I am glad you are interested in our plugin. Here are my responses:
1) Creating payment gateway interfaces is generally a bit involved. I have blown through budgets a couple of times when doing this with some standalone ecommerce solutions. But, that is really a question for the WooCommerce community. They would be able to give you specifics and maybe even a time estimate.
2) You can still sell physical products. Our plugin adds to WooCommerce functionality, it does not remove from it.
You are welcome. Please us know if you have any other questions, or if you need me to expand on this any. Cheers!
– Brook