I use lxdm on all my systems because I got tired of lightdm breaking.
I haven't switched over my current VSIDO install yet, but am now motivated to.
The memory usage of lxdm is also less than lightdm (for Void linux) -
484.0 KiB + 165.5 KiB = 649.5 KiB lxdm-binary
512.0 KiB + 203.5 KiB = 715.5 KiB lxdm-session
I think lightdm comes in around 5-6 Mib
The /etc/lxdm.conf file is easy to configure, and I think it's greeter is self-contained so you'll save a bit of overhead on the iso.
I'm pretty sure it's still developed since it's used for the lxde desktop, but it's pretty mature and does what it's suppose to do so not a lot of changes.
There's a thread in this forum about using it, may need to make some chnages to apt (preferences) so it doesn't haul in all the lxde as dependecies/recommends; easy fix.
previous lxdm link