It's never a good idea in general to glue something to fabric. In particular with lycra/spandex the purpose of the fabric is to stretch as you move. Glue's purpose is to keep something in place. Adding glue to lycra kind of defeats it's reason to exist and you'll find yourself shedding all day long.
It's always best to sew into the fabric whenever you can. It'll hold longer, it'll stretch with you, and it'll give you less breakage. You're going to want to sew through the shaft of each feather to attach them to the suit. (Note: Cheap feathers won't work for this. You'll have to pony up money to get decent quality feathers.) Another option is to sew the feathers to bias tape and attach the tape (through sewing) to the suit and layer them accordingly.
Another idea entirely: http://tiramisuwonderland.tumblr.com...-turning-out-d
I'm assuming you mean The Tooth Fairy from Rise of the Guardians? You could always try to fake the feathers by painting them on the suit.
But yes. Glue really should be a last option. Hot glue especially. If it doesn't melt the fibers (higher temps can do this) you'll find it losing it's adhesion to the feathers fast.