If this is for testing only, I don't think you need to give each distro a separate /home partition. /home for each distro could be contained within each distro's root partition (that's the default with most installation routines). That means a separate partition for each of however many distros you expect to be testing at the same time, plus a single swap partition that all the distros can use, since, in a multiboot system, you will only be using one distro at a time.
It is probably not wise to ask multiple distros to share the same /home partition--different configuration choices in the different distros could lead to very confused configuration files if they try to share a single /home partition.
It might also be useful to create an extra partition that could be used as a shared partition, sort of like a built-in "network" share, that could be used to move files among the various partitions. An external USB drive could serve the same purpose.
As for file systems, ext4 is likely best, but ext3 is perfectly serviceable, as they are both journaling file systems
; ext2 is not a journaling file system, so I would recommend against it. Again, since this is for testing, LVM probably would not be necessary.
Just a few thoughts.