I've never heard Adley before. Do quite like it but prefer Addison. I haven't heard Millen before either - is that a girl's or a boy's name? Teddy is okay but I think I would want it as a short/nickname for something because it seems quite young. An adult might want another option like Edward.
Just come across some other unusual names on a documentary I was watching that might have a similar kind of feel to Adley:
Nerilly
Febrianne
Indianna
I don't know whether the first two were made up or are established names but think they're quite cool.
I've known two girls called Addy. One was Adenike and the other Adesuwa. But at least one, possibly both, those names are Nigerian so may not be what you're after.
Also:
Avery, Amberley, Anoushka, Anika, Bailey, Bronte, Cassidy, Camryn, Cleo, Devon, Danika, Emery, Eden, Everly, Fallon, Farrah, Genesis, Giselle, Harper, Jessamy, Jerica, Kiki, Keltie, Leonie, Lorelai, Livia, Mika, Mala, Mackenna, Marissa, Neriah, Nikita, Nyah, Nia, Piper, Paloma, Quinn, Ramona, Romilly, Rowena, Saffron, Sorrell, Sadie, Tansy, Tamara, Vashti, Xanthe, Zeryn
Alfie, Archie, Arnie, Albie, Brody, Bobby, Billy, Colby, Corey, Cody, Charlie, Davey, Eddie, Freddie, Ferdi, Jamie, Jonty, Mickey, Nicky, Richie, Riley, Rory, Sammy, Stevie, Tommy, Timmy, Vinnie, Wilkie