About Alaska and Hawaii: it's an interesting point. I don't think that everybody didn't say that, but you might have made an assumption 50 years ago that Alaska would follow other recently frontier states like Arizona or Montana, and at that time Arizona was solidly Democrat and Montana strongly tilted that way in Congressional elections. As for Hawaii, most of the Representatives in the territorial period were Republicans, as was one of the first Senators, Hiram Fong. So it's entirely possible that someone making a prediction back then would have gotten it wrong.
The difference between then, and now, though, is that politics is less determined by local issues and more by ideology. Old ethnic and religious tensions and conflicts aren't as much of a factor as they once were, but evangelical vs. non-evangelical and white vs. non-white did a lot to decide how people voted in the last election, and unless a lot more Puerto Ricans go evangelical very soon, we know what the numbers will mean. There may be a few surprises, but I think we pretty much know what the trend will be.
The party “nominally” aligned with the GOP is the New Progressive Party. While many of its members are aligned with the GOP, many prominent members are national Democrats (such as ex-Govs. Pedro Rosselló and Carlos Romero Barceló, along with the current Resident Commissioner, Pedro R. Pierluisi).
Frustratingly, when the Republican-aligned ex-Governor, Luis Fortuño, ran on the 2008 and 2012 tickets, he excitedly endorsed Democrat Pierluisi (who won even as Fortuño lost). Had Pierluisi lost, he would’ve been replaced with, yup, a member of the Popular Democrats, meaning still another Democrat (although the Populares actually oppose statehood). To put it simply, the GOP didn’t even have a candidate running for the sole federal office... it was a race between two Democrats.
Aside from Fortuño’s single win in 2008, the last Republican to win the Governorship was Don Luis Ferré in 1968 (despite the Progressive Party winning on some other occasions since, but again, ALL its other Governors were Democrat-aligned, as were the Popular Democrats and its new Governor, a Populare). Those two men were the sole Republicans to win the Governorship since the popular vote was instituted in the 1940s.