agreed on the glyphosate spot spray. i use a little paint brush in areas like you describe.
forget weed barrier - weeds can establish on top of it, and the material never goes away and it makes it harder to work around your roses.
just clean it up, and then maintain. roses need a lot of tlc anyway, so if you are doing it right, you'll be there a lot working them anyway. roses are big eaters - so get a 6 week fertilizing plan.
you might try a systemic feeder/insecticide/fungicide for feeding #1 if you haven't fed for the 1st time this year yet. regarding japanese beetles - i wouldn't remove your rose bushes just because of the beetle - but it will require more work if the beetles are around like they were last year.