Re: want to coexist Ubuntu 12.10 and Lubuntu 12.10
I installed both Lubuntu and Ubuntu 64-bit 12.04 on 32 GB SD card with common /home partition for a netbook size tablet PC with detachable keyboard. I had already partitioned the SD before that using gparted and used "Other" during install to chose what to put where.
The only issue I had during install is that I wanted to put Ubuntu's grub on its partition instead of the MBR and for some reason it would not let me (on my desktop PC I have 12.04's grub on a primary partition instead of mbr due to some Win7 programs overwriting grub2). So Ubuntu on the tablet PC has no grub.
But other than that they both coexist and work fine using the same /home.
The only issue I had with Lubuntu is that by default it only installed alsa audio, which did not work (no PCM device in alsamixer). But after I added pulseaudio, the PCM device appeared in alsamixer and sound worked (analog stereo).
Not sure what you mean by "Some say Lubuntu need user to mount point after installation."
i5 650 3.2 GHz, 8 GB, nvidia GTX 550 Ti 32" 1080p | i7-4700, 8 GB, Intel HD 4600/nvidia GTX 765M 15.6" 1080p | etc.