Form that generates custom referral link upon successful completion

Design help Custom code
1

The purpose of this topic is to be able to have a contest where the user who has the most successful form completions from his/her referral link will win a prize.

I would like to create a form which does the following:

  1. Collects email address (returns an error if the address is taken).
  2. Collects preferred username (returns an error if the address is taken).
  3. Generates a shareable custom referral link which directs to a blank form each time a user fills out the form. It is imperative that we are able to track the amount of times each custom referral link leads to a successful form completion. It would be cool to have a leaderboard page where we are able to track the usernames whose custom referral links led to the most successful form fills.

Note: Every single form completion should generate a new custom referral link for the user who filled out the form to share.

Thanks!