Ha! Kings. I nearly said 'is there working cocker in there?' further up thread! She so sounded like there is a dollop of worker in there. Do you know if she's working bred or trial bred? There'll be quite some difference between the two .....
Working cockers are fabulous - active and intelligent - very sensitive and keen to please. IME they have to learn to trust you and once that's sorted will do anything you please whenever you ask. She'll need you to be firm but gentle. They are too sensitive for rough/shouty training.
The most important thing you'll ever do with your dog is get an absolutely rock solid, perfect recall - preferably to a whistle. Her instincts will encourage her to follow scents, rooting through cover and she'll cover distance very fast. Obviously, you have to be able to get her back to you - no matter what - so I would invest in a whistle (voices, for some reason, give up when you most need them) and teach her to come back to you with it. And work really, really hard at it. It'll increase the bond you have with her too.
But - your original question about biting. Have you ever watched puppies and dogs playing together? Biting is a large part of their communication. They hang off each others ears and lips and nip for attention. They also do the play bowing thing to show they're up for a game.
I've learned a lot from the way my girls interact. The adult dogs give the puppies a lot of leeway but will only play with them when they want to - it has to be on the adult dog's terms. Pup can just about dance on it's nose but it still won't get any attention if the adult isn't in the mood. I've even seen puppies launch themselves at an adult dog to try and start a game, but the adult just gets up and walks off leaving the pup behind. The puppy very quickly gets the message.
Puppy play though is different again. Put a pile of puppies together and they just have biting, chasing, play bowing, physical bundle. They don't have the ignoring thing going on but squeal loudly if someone hurts them. The routine seems to go play, nip, squeal, sit on bottom, start again. In this instance it's puppies learning about teeth, jaw strength and what's acceptable.
Puppies also are very keen to get to lick/nip faces and mouths when they're hungry - it's a baby thing.
Also - google bite inhibition by Ian Dunbar - it quite clearly explains why they do it.
However - it's not acceptable in our world. At all. So I don't tollerate any biting at all. Any hint of teeth is met with a firm no and I walk off or put the puppy down on their own somewhere. TBH, no is usually enough. I behave the same was as the adult dogs because I don't want to be treated like another puppy.
Alp- don't feel bad about teaching her about her bedroom. Keep in mind that adult dog you hope to end up with. In time, you won't have to have the gate there and she'll settle down in a variety of places without causing trouble but at the moment, she has a lot to learn.
To teach hide and seek, start with a favorite toy or small treat and let them see where you've put it. Keep it quite close to hand though. Pick a word for finding it and say that in a really happy, sing-songy voice while you lead your puppy to where you put the treat. Praise like a loon. Repeat. After a few goes, your pup won't need you to lead it to the treat. Then slightly increase the distance, vary the place and so on. Each time you change the game you might need to lead the puppy to the new element, but they'll catch on very, very quickly.
Eventually, you can be hiding many, many items and sending your dog out to find them - by name too if you like. It uses their brains and increases the level of trust they have in you which is no bad thing!