I'll give you props for providing some good links with some good information. I was going off Nawrocki's rankings, which had him as the #22 tackle, consistent with most of the reports you linked (Calloway was ranked #12). All I'm saying is I wouldn't expect him to come in and start, at any point, during his rookie season, as some others have projected him.
As for Gaither being a 5th rounder, you have to remember that was with the supplemental draft.
That's actually how I see the longer term interior lineup playing out.