Question 1:
Reply YES as you use HTTPS encryption for connections
Question 2:
For what you said about your app the reply is NO. In brief you don’t use any function inside your app that use a custom cryptography or it’s strictly medical app. The encryption that you use it’s only for data passing from app to server, nothing inside your app is encrypted (app or a part/module of app is not encrypted).
Question 3:
No you don’t use a custom crypt algorithm. That is usually used for bank app data inside the app.
Question 4:
Say NO. The US rules give an exception for apps with only HTTPS calls (that is what you do). Read here for a full explanation:
- https://developer.apple.com/forums/thread/98071
- https://www.cocoanetics.com/2017/02/itunes-connect-encryption-info/