Welcome to the forum.
You have a lot of questions but, that's what were here for.
I'll give my opinion (for what it's worth) and let the others pounce on me when I'm off base.
1. who makes Cabela's rifles?
Cabela's rifles are made by Interarms in Italy. They are the same folks who make the Lyman GPR and their rifles are good quality guns.
2. is Traditions a quality company, and why are they a lot cheaper than other companies? Are they PC for the most part?
Traditions imports their guns from Spain. The company who makes them used to sell their guns to CVA when CVA was importing sidelock style guns. In my opinion, the Spanish guns quality is not quite as good as the Italian produced guns.
PC. None of the rifles produced by any of the commercial suppliers are good reproductions of a Hawken or some of the other Plains rifles however there were some guns built in California in the 1850-1870s that looked quite a bit like the TC Hawken and similar rifles. As was said, the GPR comes about as close as any of them but it really isn't an accurate reproduction of the heavy barreled Plains rifles.
I have held a Lyman GPR in my hands, it seemed very nice, but I was very turned off by all the instructions and warnings engraved on the barrel.
All of the markings will be found on just about all of the currently produced rifles. If you can find a used, older rifle in good condition, it won't have all of this writing on it.
3. does Traditions engrave warnings and instructions all over their barrels like Lyman?
Yes. See number 2. If you don't mind refinishing the barrel you can always draw file the flats to remove the markings and then Brown the metal. Browning is more PC than blueing for a plains rifle anyway.
Replica pistol questions:
4. I have looked at Uberti replicas at local stores, they seem very nice! I notice that many online stores sell "uberti, imported by Cimarron" replicas. What's the diff between these and the Ubertis I see in stores? Do they have "Cimarron Firearms" engraved on them?
It is said that Cimarron sends a representive to Uberti's factory and hand selects the best of the bunch to sell. I believe the Cimarron name is marked on the barrels.
Hope this helps you out and if it doesn't, feel free to ask more questions.
zonie