Customize the signup process/fields

I'm working on a project using FluentCommunity that needs to allow users under 16 to register with parental consent.

My questions:

1. Has anyone customised FluentCommunity's registration process to include parental consent fields and verification?
2. What's the best technical approach - additional fields in the registration form, or a multi-step process?
3. Any WordPress plugins that work well with FluentCommunity for age verification and parental approval workflows?

Appreciate any guidance from those who've tackled similar requirements.