Turn off the Rest Visibility option at Dorico > Preferences > MusicXML Import and then try importing the file from MuseScore again.
In that dialog I have only these settings ticked:
The others tend to make sense if you’re only going to do a bit of layout work; if you’re going to actually edit/rearrange/rewrite the music itself, with other options turned on I typically find myself having to reset design and position repeatedly. Better to turn off the options from the outset.
edit: This should also fix the import of a file that originated in Dorico and was then exported to MusicXML and reimported - it certainly works here.
As to the <rest measure="yes>, Finale 27 does this too.
I don’t have a great deal of faith in Finale in general, but given their links to Michael Good and MusicXML, and the fact that updating old Finale files often involves exporting to MusicXML and then reimporting, perhaps the <rest measure="yes> is a trip hazard that Sibelius should fix.