Definitely not my cup of tea. That being said it flows well and the combo is very modern and will fit in well.
I like it but I much prefer the Mackenzie spelling.
Are you pronouncing it ayda-lynn or add-uh-lynn? If you're pronouncing it like add-uh-lynn, I'd spell it Adelyn.
Mackenzie needs the c...but other than that, cute.
Is there any particular reason you want to use that spelling? Using the real spellings will keep the "modern" feel but the name with age better.
And I don't know if it matters since it's a middle name but MacKenzie is extremely common at the elementary school where I work. (It's weird how regional naming trends can be!)