If this is based off of Debian, does it use their installer and/or the netinstall?
No, Elive uses his own Installer and own way to install, that also includes a lot of special and unique features like migrating (convert) any linux system to an Elive system and an upgrade mode install of a clean reinstall. Also can install under RAID disks, clean and very fast installation (10 minutes), check integrity of the install system, removing not-needed packages like raid daemons, preconfigure some pieces of the installed system, fix of Grub problems, automated install, automated partitioning, etc… The Elive installer is totally and entirely different of the Debian installer, using a totally different way to install (for example doesn’t unpack packages but dump a clean base system). This made the Debian Installer totally uncompatible with Elive.
