I have a S5 but I forgot the password thinking that if I locked it using android device manager the new password would allow me access but it didn't. my question is if I wipe my phone using ADM will it open the phone or would it still be locked after I wipe.
If you factory reset your phone, the lock will be gone. But all of your Data will be lost as well.
You could probably try it this way to avoid loosing all your data: Android lock screen password not being recognized