i can help you with kernel, but i can't test it because of currently broken device
can you share kernel source?
For example, about graphic glitch, probably you will need to use stock Evo libs/firmware and update gpu kernel driver using a 4.3 htc kernel, maybe ion/mdp/memory allocation code too.
for wifi you can force kernel to load prima_wlan.ko
for camera, you can try to use updates from various htc kernel, changes usually are really similar for other devices.
for sensors a mix of libs/
ramdisk/kernel editing is needed
I think we can also force camera awb calibration later, and try to test ADSP firmware from Evo (for camera/hw codec etc)
A really nice help would be a full last_kmsg and a full logcat from Evo 4G LTE, so we can understand how mem alloc is changed.