Yes - there's a long history of support for racial equality there.
Yes, and they would vote for a black man? In 1888?
This is a state that was full of people who were barely okay with competing with Irish immigration, I doubt they would choose a black Republican over a reform minded white Democrat who ran on a platform many describe as it could've been written by the Republican Convention.
Supporting voting rights for a group doesn't mean one thinks about voting one for president.
Why do you bring up competition with immigrants?
I don't any longer think MA would have voted for Douglass in 88 (I was being super generous like with your map), but it'd give him 3rd or 4th highest among all states.