Sorry, not sure what you're asking with your question!
For your second point: the method I use for calculating the screen colour is more accurate than Graves' method (and probably VTubeStudio) and this app works with PBR materials (standard shader). If neither of these things matter to you and you'd rather have the performance, use Graves' method, I wholeheartedly endorse it!
And thirdly: unfortunately VSF is a closed format and while I'd love to add support there isn't an easy avenue to doing so. It's more likely Emiliana will add the lighting effect to VSeeFace.
I'm still working on stuff with this app behind the scenes, but there will be a while before any features are introduced.