I'm curious as to what features are suggested to distinguish a Romantic from a Tonalist in this division?
I don't think it's a useful division. Another forum has twisted itself in knots trying to define romanticism and failing. Very roughly, romanticism prioritises emotion over form. Brahms, for instance, is regarded as a classicist rather than a romantic, though he gets lumped in with the romantics by dint of temporal association.
It's easier to draw the line between those who converted to serialism and those who didn't.
