What I do in your situation is start a PRIVATE tree on Ancestry with sources and see what hints get thrown out for them.
You have Walter who is a cousin! So start with him and then parents, their marriage, chilren, deaths....look for their siblings and who they married!
Then it by bit work backward in time, adding anyone as you go, across the lines and backwards.
You're only going back a very short time...
It depends on where Inmate is written and context!
Organizing them on a PRIVATE tree is the way I'd go!