I don't think you guys should be stopping workoutt altogether. Suree I guess its hard to fast but after u buka puasa u should have ample time to get a workout in. All you need is 45mins if you're just aiming to maintain.

Probably reduce to twice a week workout or something.

Regarding muscle loss I don't think you would lose much provided you got your maintenance calories in during buka puasa. IF has been ptoven to work so I don't see how different it will be in this case.