Ideas for formative assessment in interactive videos

I'm searching for ideas to enable cumulative formative feedback at each stage of an interactive video. Each question type allows some form of feedback, but using multichoice questions in a "question set" allows the user to build insight during the process and not just at the end of it. Interactive videos don't allow for question sets though. Using a series of individual multichoice questions could work, but only if the video has sufficent space and we can only position questions at a whole number of seconds into the video, not a fraction of a second.

Do you know how to ask a series of questions at a specific point in a video to give feedback after each question?

Do you know how to position multichoice questions after decimal values of a second?

Is there another method to giving cumulative formative assessment at particular points in a video that I have overlooked?