I just did a "test" with 1.02. I had a manufacturing tech finish up. There was no extra research points showing in the research bar. I switched to a new tech in the commerces area to get a trade route. When I selected the tech, it said 3 turns to finish. Still no indication in the research bar.
Then I hit "turn".
The research bar went to 60% full and it now said 1 turn remaining. And indeed it finished on the next turn.
So I am guessing that research does carry over, and to whatever tech you choose. Hard to tell if any points were lost, but it can't be many. I do think that the number of points required should be displayed; perhaps that will be done at some point. Not a large issue to me, but a convenience.
However, my experience is that if you select a tech past a specialization that has not been researched, it will research the top tech of the specialization, as you say. But I haven't checked it lately.
And I agree that you can't queue techs from different lines --- or, I don't know how to do it,