Editing the "Confirm Subscription" page dynamically

Hello all.

I am using the Membership plugin and am attempting to Integrate it with GravityForms. I have followed walkthroughs I have found on this website to accomplish the first part of the registration (https://premium.wpmudev.org/forums/topic/gravity-forms-and-membership-signup#post-232538)

I am now trying to add a different GravityForm to the "Confirm Subscription" page to require the User to enter certain information based on the membership level they have chosen. Here is my workflow:

Initial User registration http://bostonwebsitedevelopment.com/udef-tour/register/

Upon form submission -> automatically create user, log them in, and redirect them to the "Subscriptions" page to choose a subscription http://bostonwebsitedevelopment.com/udef-tour/subscriptions/

The user then chooses a subscription, and moves to the page http://bostonwebsitedevelopment.com/udef-tour/memberships/?action=registeruser&subscription=1 where the subscription=# is (obviously) going to determine which form I want to display on this page.

Is there a way I can replace the content of this page with a GravityForm that can subscribe them to the correct subscription upon successful submission?

I am aware a lot of people have asked questions about integrating with GravityForms with not much luck. Sorry if this question was already out there, as I could not find it. Any help is greatly appreciated!