1) Not sure they were considered high end in the same way custom and semi-custom 1911s are viewed today. Maybe high end for the time, but the stainless alloy used was inferior to today's stainless.
2) Yes. I don't think they made any carbon steel guns.
3) Yes, and they were only made for a couple of years.
I don't know if any shooters were putting hard use on the Randall guns back in the day, or how they would hold up. In my opinion, the Randall guns are attractive and an interesting piece of 1911 history. For serious use there are better options today in a 1911, so I view the Randalls more as collector guns.