I saw that they all got put on the 10-day IL on the 6th (yesterday) but I didn’t see anything indicating they were retroactive moves. Maybe you’re not allowed to have an effective date prior to your first game?
http://mlb.mlb.com/mlb/transactions/#month=4&year=2021&team_id=120
EDIT: I see Will Harris is retroactive to 3/29 but no one else is.
for covid, you don't go on the 10 day or 60 day DL. You go on for the length of time needed to deal with the positive or the exposure.
