Coupons w/out paid membership? Change "Apply Coupon" text? Customize Account Page?

Hello,

I’m using the Coupons add-on (w/ buddypress, as well) to create a product registration system. You guys have already helped me add images to each Membership type by helping me to write a custom plugin. I’m wondering if I could do something similar to further customize the Coupon plugin. Ideally, it would be possible to enable coupons without making the memberships paid, but I can see that this probably seems really illogical and not how the coupon add-on was developed behave.

Here’s what I’d like to do:

1. Change the “Apply Coupon” text on the coupon entry screen to “Enter Code”

2. Remove references to price, i.e. “you will pay USD 1.00 for permanent access” or “Total: USD 1.00”.

3. If it’s possible to remove the invoicing section from the Account page, that would be good too.

4. Also on the account page, instead of “change” next to “Your Membership,” I’d like it to say “Register a Product”

5. Can I have certain items in my navbar for logged in users, and certain items in my navbar for non-logged in users?