I'm using RCP and I'm trying to come up with a good User Profile setup.
I want a User Directory and Profile Pages and custom fields and conditionals and filters etc etc
Does Metabox play nice with Restrict Content Pro? I want RCP to manage signups and then something to do a good job interacting with users and displaying their info
The extension MB User Profile (MBUP) helps you to create the user meta for users when editing users in the backend. In the frontend, MBUP has its own shortcodes to create a register/login/profile form while Restrict Content Pro (RCP) also has its own same shortcodes.
So I think you can use both MBUP and RCP to create a form in a specific case if you want. To create custom fields for the RCP form, please follow its documentation https://help.ithemes.com/hc/en-us/articles/360053124813.