If your DVD drive had shown up in your hardware for linux, there shouldn't be any reason why FreeBSD (PC-BSD) wouldn't pick it up as well. On the flash drive media, you would likely see something along the lines of ICH1xxx, ICH2xxx... etc, followed by Intel 82800 for USB support. Your flash drive would show up after KDE started up or after you plugged it in after KDE was up and running. I've had one system that refused to boot when the USB flash drive was plugged in at all, regardless of whether it was Windows or *nix OS'es.
Go through your /var/log/messages file to verify what is or isn't recognized. If your DVD(R/RW) drive(s) still aren't being recognized, check your IDE cables and connections. If still not, you may have to manually go through an install using FreeBSD 7.x and skip using PC-BSD to configure your kernel configuration.