Yes. PayPal Email and Receiver Email. Usually the same.
You definitely will need a checkout page. You can just create one, call it "Checkout" and leave it blank. Then navigate to Woocommerce > settings > checkout and select it in the "Checkout page" selection box. This will now declare it as the checkout base page.
Woocommerce usually sets these pages up for you but maybe you accidentally deleted it. That should do the trick.