- It is situational. Maybe stylized animated mask transition would look better.
- Not bad at all
- Multiply screen UVs by tiling factor before pluggin them to flipbook node. I would probably prefer having dither pattern in UV space of object rather than screen space though.
- I did not really dive deep in TemporalAA, but I think it is safe to assume that DitherTemporalAA node with TemporalAA disabled is just a simple screen-space noise. So your players should not be able to turn it off, unless they hack into the shader.
About you not having control over DitherTemporalAA results, well you can peak inside and maybe duplicate whole function and modify it as need. There is nothing fancy inside.