Seraphim was a Czech or Eastern European label which then may have gotten bought out by Angel/EMI. RCA Victrola are later re-pressings of music found on His Master's Voice 78's and RCA Red Seal (both shellac). Most RCA Red Seal recordings were re-pressed on the Shaded Dog or RCA Vault Treasure labels. Odessey is a classical budget label from Sony.
Recordings were often recorded in both mono and in stereo as more and more folks bought stereo systems. There are examples of recordings which were mono but artificially made into stereo and stereo artificially made into mono. If both mono and stereo recordings were in production, there should be either an M or an S next to the catalogue number.
The grooves found in mono records that date prior to the 1960's are wider. The microgroove record was an early attempt to get more play on the 33&1/3 and long playing 45's. Into the 1960's, the grooves were by industry standards more narrow and the grooves were cut deeper. Some mono cartridges like the Ortofon SPU's are ideal for the older and wider grooves.
From my understanding, the higher quality dual mono cartridges such as the Lyra's can play on both stereo and mono records just fine. I believe that those cartridges which are strapped stereo cartridges in order to make them into mono cartridges will be the ones that cause damage to a stereo record. I've never heard of any mono cartridge being un-playable on any mono record of any sort, although admittedly, those shellac records do make me a bit uneasy.
Mono labels that I typically collect are RCA Shaded Dog, Columbia 6 Eye Grey and Red, Epic, Decca, London, Melodiya, Monitor, Westminster, Archive Productions and Deutsche Grammophone.
Personally, I'd aim for either the Miyajima Zero or the Lyra (especially the Titan). Ortofon makes both the SPU's and the Cadenza. Benz micro gets good reviews. For entry level, Jonathan Carr recommended the Audio Technica AT 33 mono. The upper level Grado moving iron cartridges have gotten good reviews on some of the audiophile websites.
One last note is that the older 200 gram platters which date between the shellac days and the flimsy stereo days sound great to my ear/s but they will sound even better with a thorough cleaning.