I live in the US - originally from the south but now living in the northeast.
I really like Madeleine as a nod to my French roots, and my husband’s Italian background. It feels very European and sophisticated.
Usually, I’d pronounce the more common spelling of Madeline as “Mad-eh-line” vs “Mad-eh-lyn”, unless otherwise told. I tend to prefer the “-line” to “-lyn” ending better.
I feel like I’d pronounce Madeleine like “Mad-eh-lane” or “Mad-eh-lane-uh”. It could be “Mad-eh-line” though.
Mad (eh) lehn is the [name_u]French[/name_u] pronunciation. If you want mad-dah-lay-nah, I’d go for the Italian [name_f]Maddalena[/name_f]. [name_f]Madelaine[/name_f] is mad-eh-laine, too, so that may appeal? I’d avoid [name_f]Madeleine[/name_f] if you don’t want the “lehn” ending, myself, but it is a nice name.
I’d say line for [name_f]Madeline[/name_f], len for [name_f]Madeleine[/name_f] (although in practice I think my len is relatively similar to my lin), lin for [name_f]Madelyn[/name_f]
Agree with pp that I’d use [name_f]Maddalena[/name_f] if you wanted that pronunciation.