I certainly don't have the time to investigate or implement this. However I would be willing to help integrate the work done by anyone else.

Now added, thanks. The flights data base is taken from a periodic dump of the OW timetable, and is then supplanted by reports here. For instance, I guess I'll need to update AY with the changes to HEL-SIN/HKG/BKK ... if someone can distil exactly what is needed there, then I can make the change fairly easily (e.g. delete HEL-BKK, add HEL-HKG or whatever is happening, and don't forget the return routes which may or may not be the same). By collectively doing the research on these changes and posting them to this thread, it makes it much easier for me to then make the changes to the tool.

If you're reporting a problem with the OWE validator, then I'd appreciate a link using the "Link to this itinerary" feature, as it provides a fast, accurate method of reproducing the problem. This feature can also be used when you would like others to comment on a proposed itinerary.
Yes - although they might need to be added manually. The tool makes the assumption that they operate all year, so I guess one downside of the tool is that you could be misled into thinking that seasonal routes operate all year - but you'll quickly discover this when you progress to the next stage and start to pick dates/times for flights.