With access to the source, it should be possible to export them to HTML5 using Adobe's flash authoring tools. I've never tried it though, and I don't know how good the HTML5 versions would be.
Edit: huh, it kinda runs with Mozilla's Flash-runtime replacement, Shumway. Another few rounds of bugfixes and we might not need any Adobe code to play these files just as they are.
The problem with most current Flash-to-HTML5 conversions is that they only barely support ActionScript, if at all. So anything meaningfully interactive (like minigames) is pretty much out.
Shumway makes it sound like "we got this" (which then discourages someone like me--someone who has a ton of knowledge of compiler design and a lot of background specifically with JavaScript-based language but almost no interest in duplicating effort, someone who would normally see this call to action and go "oh, I'll add this to my todo list"--from even spending much time researching the current space). Are you saying Shumway only "barely" supports ActionScript?
There are several such projects - swfdec, lightspark, gnash, etc. From what I've seen of them, they all underestimated the amount of effort. Most of them just petered out. So if you're going for it, I would worry less about duplicating effort and more about setting realistic goals for the project.
I wonder if we could wrap them in an OpenFL app exported to HTML5. OpenFL can render SWF content; as for the triggers for the interactive bits that might require access to the original source, alternatively it could be reproduced, it's usually just a matter of "click here to go to scene X" and the hidden scenes themselves would be extant already.
Edit: huh, it kinda runs with Mozilla's Flash-runtime replacement, Shumway. Another few rounds of bugfixes and we might not need any Adobe code to play these files just as they are.