I believe it was S. who asked if Sonnyboy could be part Great Pyrenees. Here’s the reasons why not. Great Pyrenees have double dew claws on their hind legs. Sonnyboy has no dewclaws on his back legs.
Things in favor. Sonnyboy weighs 100 lbs. He has thicker, almost mane-like fur around his neck, and most importantly, the exact same nose.
So, now I’m leaning away from big hound toward Great Pyrenees. They’re not incredibly common dogs, in general, but a lot of farmers around here have them in with their goats.
Also, a pug tried to bite him on the head today, but he remained unfazed. It cracks me up how much he wants the cats to like him and how unconcerned he is with other dogs.
Tiny Cat Pants 
A good friend of mine has a Great Pyrenees. Arthur runs like you’ve described Sonny running. Does Sonny drool, too?
Ours is half Pyr. She doesn’t have the double dewclaws either. She is a lot softer than a Pyr but she has the independent ‘do what I want’ disposition of one. I’m told Pyr are very independent and stubborn.
I wish my aunt could meet him. She raised Pyrenees for years and could tell you on sight. Depending on where he’s from, he might even be a descendant of one of the dogs she raised and sold in the region to help care for livestock.
She had some of the best dogs in the state. Hilarious personalities, too.
So glad to hear y’all are so happy and still getting to know each other.
Oh, he drools. A lot. Plus, I think this explains why his ears are set so low on his head. All the Pyrenees pictures I see on the internet show their ears in exactly the same spot.
The Ears do look potentially right. My brother and SIL have had a succession of many GPyrs for 10-15 years now and I’ve only seen one short-coated one. Let me see if I can get a picture of him (Snoopy) to send you.
We’re thinking, because of his short coat and mostly Lab look, that we’d be taking a Pyrenees grandparent, still. Just someone to give him hugeness, ears, nose, huge paws, and some longish fur.
I didn’t realize he was so big! I was thinking on the 70-80 lb range.
My big dog(only 80 lbs) is suspected of having either Pyr or Great Dane somewhere in there. His head is shaped like Sonnyboy’s, but he has double dewclaws. And he’s white and black with blue merle and few sandy brown patches. So he’s just a mystery.
I have to try to get a picture of him with a regular lab. Because, in general, he looks just like a lab that someone embiggened. But every lab owner we’ve run into has been gobsmacked at his size.