I would pronounce
Adeline the way you do, "AD-uh-line" in English (default pronunciation for me) and "ad-uh-LEEN" in French.
Adelyn looks like an over-the-counter medication to me. My brain won't let it be a variant of "Sweet
Adeline."
Adalynn I thought was more like
Ada +
Lynn, but maybe it's closer to
Adelyn.
The old barbershop quartet standard, "Sweet
Adeline" is what I think of when I see / hear it. So cute. :0)