Should I wait to start running ads until my LLC and EIN are in and I’ve got a company credit card set up? Or, can I start and go back and enter/change that info over?

I would start that process now with the establishment of the company. You need a payment processor. So if you can set it up without a company, we can start running ads now and change it later.

Please see the conversations of students who have been through this process here: https://www.facebook.com/groups/392775941293956/permalink/531685810736301/ and https://www.facebook.com/groups/392775941293956/permalink/531479327423616/