Based on reported decisions (mostly SCA-related; FISA stuff is not public), Microsoft is the cloud provider who's litigated the most on behalf of client privacy. e.g., It was the Microsoft Ireland case, challenging the extraterritoriality of the Stored Communications Act, that ultimately led to the CLOUD Act.

Microsoft understands at a corporate level that it's in their business interest (as a global vendor) for local lawful access regimes to be as narrow as possible. Their pushback here is understandable; if they're not seen as trustworthy by the US government, it potentially undermines a lot of the latitude they're trying to fight for.

Not until it was unveiled. Also still allowing. none has any backbone.