App Store - are "legal contract" kind of apps permitted?
Only Apple's review staff can answer this question. Any answer offered here can only be an opinion.

As the Apple's App Store guidelines stand today, the app may be accepted. However, Apple reserves the right to reject apps that carve new niches and push boundaries.

Contact Apple

Talk to Apple's App Store staff about how best to approach your app and how to avoid being rejected:


  App Review
  
  Find out the status of your app and submit general questions for the App Review Team.