they are but that's going to depend on what flights are available out of Myanmar and also whether he can transit in SG as I don't think he'll be able to buy 2 separate tickets
As it stands it's 7 nights then you can leave if you test negative. It's SHA+ hotels only so not every hotel.
If this goes ahead, and I'm still not convinced it will, then there will be a lot of info/changes between now and 1 July. I wouldn't book anything yet.