Crazy Red Adolescent Boy Dog

I affectionately refer to Fritz with many crazy-like names.  I don't use his name much (habit that deserves a post of its' own...) so I find other things to call him.  Today he was red beast, crazy red boy, and goofy red kid... I think.

Our training today was great in many ways.

1. He never stopped taking food.  He started showing signs of being disinterested, so I stopped before he stopped.
2. He remembered hand targeting after only a couple sessions.  He hasn't worked on it since he was at my house in September.
3. His Gentle Leader behavior was functional.  He'll still put his nose through the loop and allow it to be buckled without bucking-bronco tactics.
4. The Tug-A-Jug is still exciting.  As is the Kong Genius.
5. He was able to reorient at the door and I was proactive and held his collar to prevent leaping off the deck (he likes to launch from deck to sidewalk, completely skipping the 3 steps and hauling the person on the other end of the leash with).
6. He didn't pee on my shoes in greeting...

September... we definitely have snow now!

I brought an assortment of kibbles I have at home (TOTW High Prairie, Fromm Salmon, Fromm Duck, Kirkland Chicken and Rice) and some Old Mother Hubbard assorted mini-biscuits.  We also used treats from his house--peanut butter biscuits, dried chicken jerky, and soft beef treats.  He was very alert and in tune when we encountered another dog (a good distance away).  I was able to get him to reorient and sufficiently reinforce/keep his attention every time but one.  He did wuff! a couple times but no leaping dog behavior, just a lot of "stop and stare" that was fairly easy for me to reengage him from.  Very little Gentle Leader frustration behavior (he perfectly demonstrated the difference between thick and thin nose loop preference that I'd tried to explain previously), and incredibly responsive to the slightest pressure.

Not-so-successful.

1. He was still launching at me pretty regularly.  It decreases significantly each time I see him, but he's still doing it.  He's huge and it hurts.  It frustrates him when he doesn't get my attention that way, so then he gets mouthy. I was sorta able to redirect to a toy and sorta able to engage him in training... sometimes.  I know he needs a better way to greet me, but if I get down on his level I get pee on my shoes.  If I engage with him upon first arrival, I get pee on my shoes/pants/whatever is nearby.  (He's a huge submissive peer...)
2. Nail trim.  When he stayed with me I trimmed his nails almost every day.  By the time he left, he'd lay on his side and let me trim all four feet without mouthing me.  He was relentless today.  I actually needed another hand, which I haven't needed with him in quite a while.  A toy in his mouth was not sufficiently engaging, he wanted to mouth ME.

I'm not sure if mouthy was just a "thing" today or what's going on with that.  He's always been a mouth-oriented dog, he samples everything, but I can't remember it being this significant before.  Is this something that needs to be addressed, or will it go away?

Greetings clearly need help, but I'm not sure how.  Crating hasn't helped in the past.  He gets all wiggly and pees as I unlatch the door.  I've thought about crating + dropping food in without eye contact, but I doubt he'd eat it, so... ineffective.

And my biggest struggling point ever--teaching the owner leash handling techniques with a Gentle Leader on.  Kristen and I have talked about it extensively and not come to any real conclusions... anyone else have suggestions other than go ride a horse (seriously... people who ride/have ridden have excellent leash handling skills)?