To answer in general, I'd recommend using a separate video tool (Camtasia, Adobe Premiere Pro are two that I know of) and then "slice and dice" the video to get the sections that I really need. That usually resolves the size and processing problems.
In a few cases when we couldn't do that, I ended up cutting the video into eight separate segments. The learner needs to watch all the segments to complete the class, but can watch them in any order.
Can you set triggers on embedded video? Beyond "when media starts" or "when media completes," no. You need to have something else on screen to have triggers working here. (At least in my experience.)
Controlling the video (rewinding but not fast-forwarding) is set through Player options.
As for linking the videos to an external site - including an internal Sharepoint page - that would be the easiest approach by far. So perhaps you can consider "snipping" the segments that you want, and then up front (and at the end) put in a link to the longer video, hopefully hosted on a site like Vimeo or YouTube.
