Since the nRF9160 reserved pins are never used, Is there any issue leaving them out of the footprint?
I would place copper keepouts under the reserved pin areas to ensure that nothing end up under them.
Our manufacturer is having issues with paste transfer through the small apertures. At the moment we've told them that it's ok if there isn't sufficient paste on the reserved pads since they aren't connected to anything. I'd rather remove the reserved pads and paste mask to completely eliminate the problem.
I don't see an issue with this, just thought I'd double check.
BR,
-- Glenn