Hi Wolfgang,
It all depends how you interpret the new EU regulations, and that is a big subject of controversy about it in the E-commerce circles. Different lawyers give different advices and the subject is sure not a settled one.
E.g. The button that must say "Buy" is the one that is related to the firm commitment to pay. You can configure that button in CBSubs in your payment gateway setting.
Regarding the 5 terms your lawyer suggests for approval there are 2 ways, either a single checkmark with 5 links in the terms and conditions. Or just add mandatory checkmark fields to CB's registration page (CB 1.9). For CB 2.0 we have added a "Terms" field-type where you can have as many as your lawyer wishes.
If you want to vary the button of CB's registration page instead of the one of your CBSubs payment page, then you would need to change its language translation, or to apply a bit of jQuery to it.
Best Regards,