Well: these are some ideas about it. Not quite that professional ones, but they ought to do OK.
PAL TV is 25fps 720x576px-size. If you can re-render your video material, you need to produce a 25fps video, be it interlaced (which gives you the extra motion smoothness of having 50 fields per second) or plain progressive (which will look perfectly fine anyway). If that’s not possible, then you ought to convert your 24fps movie to 25fps, be it by simply making every second use 25 frames of the original material instead of 24, so shortening its duration (which could be an issue, sound-sync-wise); or by effectively recalculating its frames to maintain its original length via some timestretch feature in your video app.
One thing to be aware of is fine horizontal detail flickering on CRT-based TV sets because of their interlaced nature (usually one solves this by introducing a bit of vertical blur here and there, or everywhere if there is no other way around it). Excess luminance and chrominance can be a problem, too, but you could just apply your video editing or compositing app’s typical “broadcast safe” plugin and more or less forget about it. These two issues probably won’t apply for LCD TVs, anyway.
You ought to check how a TV set’s brightness and contrast affect your video’s, too, as they are different from a computer monitor’s, and possibly filter it accordingly.
The most critical issue would be making sure that all text, icons and such are not so close to the screen borders that they disappear behind the TV set’s framing, so to speak. Most video apps provide “title safe” overlays to be able to check for that. If you can’t do anything about it, a passable solution could be to scale the video and leave some sort of border around the image, I guess.
Ultimately, you need to check things via a real TV set. If you can’t hook one to your computer, you could burn DVD-RWs and test things with a DVD player.
(The interactivity part of the project is rather beyond me, I am afraid)
