Yes, you can modify the signup page to have less fields. All of the fields are required, but you can replace them with hidden fields and give them a default value (exa: You can make a hidden field for address and give it the default value of "111 Main St" and then after they've joined they can go back and change it). The minimum fields you can have on the join page is:
Technically, name is not required (but we do not recommend removing it). Also, technically you could give them a default password, but we do not recommend that either.
A. With Direct Payment the software has to be set as FREE.
This is because with Direct Payment a person signs up before making payment.
In short, the order process for Direct Payment is completely different than the software not using Direct Payment.
After you've turned on direct payment, you need to then setup the member variables under "Member Variables" and setup variables for the button details. The document below describes more how the buttons work and the exact titles to use for the member variables when setting them up.