Being deaf, and wanting a better ATC experience, I would like to know if VoxATC allows a similar interface as the default FSX/P3D has, where text commands are sent and received - or is it all done by voice and audio only? Can a deaf person use this, is specifically what I am asking

Yes what atc says is in text, but it expects to hear a vocal response from you. You don't choose a response. Radar contact, pro atc x, or pfe would be better for you. Voice is kinda the point of vox atc.