Movie Studio 18 does not support mxf. files. You need at least Movie Studio Pro. Edit, or Post for mxf. Movie Studio 18 only supports mxf files. You could convert them with VLC player to MP4 files to use in MS 18.
In theory within the program for editing use, (or VLC player if just playing back the files) then yes. Whether Windows can play back such files natively in their players is another matter.
Do be aware I am going by the specs pages and I am not a Vegas Pro user. You may need to check for certain at the Vegascreatives website and forums for confirmation.
Do also be aware by going for a 365 version you are committing yourself to a years subscription and may be penalized for leaving early. It's not that apparent unless you really look at the T&Cs but it is standard practice for any rented software.
Also check your camera makers website to see if there is a downloadable codec that allows Windows to see the files. It's unusual for such a manufacturer not to supply one. You will still need The Vegas Pro editor to edit as such codecs are not normally transferable from one platform to another.