I don't know anything about the limitations that vista may have with bootloaders, but I have dual-booted FreeBSD and ArchLinux. It doesn't really matter what order, but FreeBSD generally must have root in one of the four primary slices, so it tends to be simpler to install FreeBSD before linux.
You'll also eventually want to move some piece of data from one install to another and won't have a thumb drive handy, so it makes sense to leave a few hundred MB for a fat32 slice as well.
Linux installs rather well in logical slices, and grub does a fine job of booting it (I don't recall precisely, but I think the FreeBSD bootloader can handle this as well).