1. AR 350-1 still refers to FM 21-20. TC 3-22.20 reads exactly the same for the APFT.
2. A diagnostic can be given everyday if the commander wants to do that.
3. Yes and if they did, they would face UCMJ.
4. You would be allowed 90 days for recovery on a 6 month profile. FM21-20 says twice the length of the profile and not to exceed 90 days. The new TC does not give 2x the length of the profile as a guideline and there has been no guidance from DA to supersede AR 350-1. It specifically says to use FM 21-20.
5. If they truly care about soldiers they will give you a few days notice. They can however, give it to you at anytime because you need to be able to pass a record test at anytime.
If you have a passing record test, 4 months need to separate record tests. You must take two record tests a year or be flagged. If you fail a recordyou will be flagged and you must take another record within 90 days.