I have communication success!
For those who stumble across this thread in the future looking for insight on a Keyence SR series camera talking to LabView via serial USB using a Keyence SR-UR1, I used the following:
On the Keyence side,
SR-UR1 set to Dsub 9pin config set to 2:SD, 3:RD, and USB setting set to USB-COM. Everything else default.
SR camera set to communicate at 115200 baud, 8, E, 1.
On the NI Max side in Visa testing,
Communications set to 115200, 8, E, 1, Xon/Xoff
Commands to trigger camera: LON\r to scan barcode\image and BUSYSTAT\r to determine if camera is ready to scan. (We use this at the start of our LabView project to confirm it's actually going to work when we want it to.)
Now I just have to figure out how to remove the Motorola scanner settings and replace them with Keyence in the project. Time to watch some training videos.