All we have right now is the legislation itself. I’m sure the MOL will soon publish guidelines but they haven’t yet–at least I haven’t seen them the last time I checked the MOL site this morning. But here’s my take based on what I think we do know so far–basic rule of thumb in working thru these situations is that employee gets either the contractual or ESA  sick leave, WHICHEVER IS MORE GENEROUS:
1. Yes, employees would NOT be eligible if they already have the equivalent 3 days’ paid leave entitlement or more
2. No, I disagree on this point. My reading is that the allotment isn’t just paid sick days but paid sick days for COVID-related reasons. Thus, if the previous sick leave wasn’t due to COVID, it wouldn’t count against the employee’s allotment.
3. Yes, that’s correct
4. Yes, that’s also correct
Remember, when in doubt, go with the most generous allotment. And keep checking the MOL site for guidelines. Hope this helps. Great questions. Glenn