Who would theoretically vote for the Republican Party from Fremont through Trump

[Orser67]

Another common thread worth mentioning is opposition to immigration.

At least 2/3rds of the current GOP and likely higher but more specifically:

I agree with a lot of the groups you listed, but given how important the South is to today's Republican Party, I think 2/3 is a little high. Prior to the Civil War (and especially in 1856) Republicans had essentially no support in the South, and only minimal support in the border states. Those who would become Southern unionists mostly voted for Fillmore in 1856 and for Bell in 1860.

[Orser67]

Another region that has consistently been pro-Republican is the PA-NY border region known as the Twin tiers. Well, except for in 1912 and 1964, two elections that seem to account for a lot of broken streaks.