The input monitor level is for the headphone amp, so no, it doesn't effect the recording. No clue on "monitor SW" though.
I'd leave the UA5 out of a board patch, if for no other reason than the feed from a board can be (and usually is) really hot, and the UA5 would just be adding more gain to the signal. I've got a bag I carry specifically for board patches, it has every combination of cables you can imagine, all terminating in a mini-plug (XLR>mini, RCA>mini, 1/4">mini, etc.). As for patching out of other rigs, I'd see no real reason not to do it, other than adding more equipment to the lineage (i.e. KM184>V3>DAP1>UA5>JB3)