I'm seeing conflicting info online about the exit rows on "version 1" (on United's website here) of 737-800. Hoping someone here can help.

1. Do either of the exit rows have the tray tables in the armrests? I hate how those limit seat width...
2. Are bags allowed under the seat in front of you during takeoff+landing? Or is that disallowed, even for small backpacks? If it is disallowed, is this for both rows or just row 21?
3. Other than row 20 not reclining, is there any other difference between the rows?

Thank you!