Decent breakthrough today.
Basically, I finally got the Nxtbotguard streaming solution to work with my current implementation without modifying the Nanohttpd java file. That's the middle canvas element in the image. Still not entirely sure how it works, as I have borrowed a fair amount of code.
Also using the Nxtbotguard solution I have implemented the bottom two arrow buttons (as images) which respond as expected when clicked (using Jquery, which seems awesome and I really need to learn more about) Nothing works with the NXT...yet.
The biggest issue is updating text however. I want to update the ambient light value from the NXT through dynamic text, and I am a bit of a standstill how to do that...currently trying to use Canvas, like the streaming image solution, but it doesn't work. Yet.
Still a lot to do, but might actually see a bit of progress at last...