"The drafting of Evans seemed to indicate that the Rams will keep Joseph Noteboom at guard for the foreseeable future, and that the team views Evans as a possible replacement for Whitworth whenever he retires."
I don't think drafting Evans says anything about who is Whit's heir apparent. IMO the Rams are simply assembling some OL talent for Kromer to work with, the intent being that the Rams will have OL depth this year and have someone ready to step in for Whit next year. And maybe that ends up being Evans, but I doubt anyone on the Rams know that at this point.
For this season Evans (and Edwards, and possibly Demby, and possibly others as well) will be cross-trained in multiple positions, a few of these guys will make the final 53, a couple of them will be active on gameday, and someone is going to get 1st team reps on Wednesday's when Whit gets his veteran day off.
Next year the Rams will figure out who their best 5 OL are and then figure out where they should all play. Maybe Evans ends up at LT after all, but to pencil him in right now as the 2020 starter at LT seems incredibly premature.
AlbaNY_Ram