Wow, thanks for finding Leslie Sr.'s obit! Falsterden is right, I did check his parents and siblings to see if Leslie and possibly Lucille ended up with them, but came up empty. I did find something interesting in my collection of old photos - a photo purported to be of Leslie, taken in February 1920. He is standing with an unidentified smaller girl. Leslie's mom Estella would've still been alive at this time, although his father had passed a few months before.
I am the person who created the Find-A-Grave memorials for Leslie Sr. and Stella, yes. I have searched Lakewood Cemetery's online index of graves but didn't see a likely candidate for my Leslie.
I'm going to dig into those other newspaper archives mentioned in the first reply. I have a subscription to newspaperarchive.com, which does have a good collection of Albert Lea's newspapers, but doesn't have Minneapolis ones. Maybe I'll find more clues in some other newspapers.