I'm starting to get in over my head. I have a Sony, that when switched into VCR mode, allows me to connect any RCA device via the RCA to mini jack connector. I also have S-video, Firewire and USB, but have never tried to put video onto the camera with these - although I know that I could via Firewire.
Looks like your second camcorder will work. It has composite in/out, s-video in/out..
http://www.easycamcorders.com/specs/JVC--GR-D72.htm