yes, to use the tool "meld" (included in elive, amazing tool!), to compare the directories (or better just the files like passwd, shadow, group), to see if there's an issue with the UID's as you said
but it can be a slow task / process, maybe better that just me do tests here, also, efi stills better implementation
I think that ther's some "virtualbox images" that can be downloaded, ready to use images 
Somebody should publish elive images for those virtualized environments 
https://forum.elivelinux.org/t/elive-ready-to-use-in-downloadable-formats/1130
