MT points well taken. I failed to mention that I have no legit experience with photography. I am into creativity art and music. As a teacher I'd like the ability to film my students, create documentary narratives, and have the ability to shoot my kids playing sports from time to time.
I do assume that there is enough of a difference between the 4 bodies I listed that definitive differences can be pointed out.
I have been drawn to DSLR and sold my Canon HFS20 because the DOF and cinematic quality was to die for. Now I see that low light performance, white balance, color neutrality, cinematic quality, aliasing, moire, focus, etc matter
I'm just not experienced enough to do it without sincere and educated advice.
As far as the second questions, thoughts on new vs. used/refurbished? I'd like to save $$$ but not compromise quality, value, and long-term integrity if something breaks.