Just a quick follow-up. Suthriel and rosegoldslugs, your suggestions were on the money.
An emissive plane with the media player texture on it gets you half of the way there. You can see it affecting all reflective surfaces, including ones with blurry reflections. But it has a limitation - it is not a genuine source of light. Therefore the diffuse component of all shaders do not seem to receive illumination from this plane as far as I can see. Some objects, like my seats, come out essentially black not matter how bright this emissive plane is.
So the second half of your Suthriel’s solution kicks in. I pre-blurred the same image sequence and fed that into a rectangle light’s texture slot. This does a pretty good job of mimicking the effect of a truly textured area light source. This technique has two limitations. 1. you have to manually double handle all images sequences to pre-blur them, import them, hook them up, trigger them in a level sequence etc. 2. There doesn’t seem to be a way to tell a rectangle light NOT to appear in reflections. So your nice, sharp reflections from the emissive plane are doubled up with soft reflections of the rectangle light. But in terms of the rendered images, this compromise is not huge.
So thanks guys for un-blocking me and letting me get back to making cool pictures. I wrapped up the above technique into a blueprint light/plane actor for easier handling.
If anyone out there knows how to get image sequences playing as the texture on a ray traced rectangle light, per the original question, please pitch in. The results would be visually superior and the need to double handle all image sequences would disappear.
Cheers!