what would be the best circuitry to drive all 4 outputs properly?
Beauty is in the eyes of the beholder.
Before there was arduino, there is a company called 4d systems that marketed (and still markets) similar stuff (aka shields). One of the more impressive items they marketed is called picaso, a vga signal generator on a shield.
Google it and take a look at its video buffer stages - one of the more elegantly designed buffers in my view.
To me, a proper solution here are four independently buffered outputs, aka picaso.