It's not a stretch though. It's right there and makes perfect sense as a nickname. I know changing the spelling on anything is a terrible sin on BTN but it's really not that big of a deal.
A stretch would be like, "We named her
Emmaline but call her
Ali because look, it's got -ali- in the middle there!"
Isadora Evander Larkin
Pax Walden Grey
www.behindthename.com/pnl/59411