This isn't a real answer to your question, but it is some hopefully useful information:
according to https://wiki.archlinux.org/index.php/Overlay_filesystem
"Overlayfs has been in the linux kernel since 3.18"
according to the answer and the comments here >>Which Android runs which Linux kernel?<<
linux kernel >3.18 seems rare in Android. If your kernel is >=3.18 you may be able to use some terminal commands to manually mount it how you want, I think your best bet would be looking up linux commands for using overlayfs.