So if I understand you correctly, I can assign keys that are not needed on the universal remote to a function which is labeled/available on the oem remote. Now my concern is (a) will there be enough "spare" buttons on the uei remote to give me all the special functions I need to duplicate the original and (b) can the programming be done without a cable and without having the original remote for learning?

Regarding remotes, does the 15-134 have enough re-assignable buttons for my purposes?

What about a one for all urc 10820? (will it work)

RCA RCRP05BR? (will it work)

If I buy a used Comcast remote, which kind should I look for, and will it have enough free buttons?