For Q4 - I saw my submission was "Accepted" so I stopped doing the contest and went for a rest. But after the contest when I checked my rank, I could only see 3 problems solved which significantly impacted my rank. Also, the status of that submission had changed to "Internal Error".

Proof:
https://leetcode.com/contest/weekly-contest-179/submissions/detail/310392950/

1. The submission was during the contest.
2. The unchanged code of the submission is an Accpeted solution.