Nope. It's BS that's about 30 years out of date. Here's an article about it. http://companionanimalsolutions.com/blogs/dangers-of-alpha-rolling/
You guys need the help of a REAL trainer, not some crap pet smart cesar milan disciple. In fact, I'd complain about this trainer recommending this. Seriously, it's dangerous.
I already see NUMEROUS errors in your training process.
First, you don't give a dog a toy to get them to stop biting. You see "Here's a toy to play with instead of biting me." The dog sees "If I bite you, I get a toy and you play with me."
Second, "Squealing" is a crap technique. The only reason it occasionally works is because it sound distracts the dog. It doesn't make the dog think you are a hurt puppy, and even if it did, why would you want to be a hurt dog?
Third, you tie her to a tree? A puppy with 2 out of 3 breeds that are NOTORIOUS for animal aggression and escaping? I'm all for time outs, but that's what dog beds are for. We use a "go to bed" time out command. My GSD hears it, runs to his bed, lays down, and stays until he's released.
Fourth, the second someone says they walk their dog and give plenty of physical and mental exercise, red flags start waving. The dog is getting 5-10 walks, play sessions, training sessions, obedience sessions, and such a day, each for 15-30 minutes?
Fifth, She's A Puppy! She will grow out of this.
To me, the next steps would be to stop all the BS crap you guys are doing. I would then INSTIGATE play everytime the puppy is up and moving. Don't let her start it - this is when most biting behaviour occurs. The pup should NEVER be roughhoused with - no hand play, no body play, no hands or forarms in her mouth. And NO TUG until she can get this under control a bit more.
She's plenty old to be told "leave it" and put into a sit everytime she comes at your hands. She HAS to stay in sit until she calms slightly and then you can release her (I use 'ok') and start the play over with a toy.