Hi Alana. Sorry for the late reply. Hopefully this will be still help.
- re 1 - Yes, you should be able to change that setting safely. The setting applies immediately but the Workshop should just check the existence of the example submission assessment. So students should never be asked to do them again.
- re 2 - Yes, you should be even able to use the random allocation now without removing the existing allocations. And that should just add allocations to where they are missing.