I am looking for help, please do not be rude. If you feel like being rude please do not respond.
JethrosMom, you will get responses on this list from people who don't offer a whole lot of help. They are the minority. I like to think that they mean well, but just that they don't really know how to give meaningful advice. It is one thing to tell someone that they need to work on something and another thing to actually suggest how to work on it.
Here are my suggestions. I hope they are helpful.
Carve out some time to exercise your dog. It sounds like you have a pretty good start on the physical exercise but that you might not be doing a whole lot of mental exercise. One easy way to tire his brain is by reserving half of his food portion and use it to reward basic obedience behaviors around the house. Put him on leash and ask that he follow you around the house while you do your regular house work, sitting and waiting while you do your tasks. Reward him with bits of kibble that you carry with you. You have to feed him his food anyway--you might as well get some mileage out of it by making him earn it in exchange for proper behavior.
Not only does this give his brain something to think about and tire him out, it also promotes calm behavior while on leash. Right now, every time you put on the leash it is to go somewhere and be active. By only associating it with exciting things you are conditioning him to get excited by the leash. By leashing him in the house, you are counteracting that effect and teaching him that being on leash is about being calm and listening to you. You don't have to do it all day long, maybe just during the times when the baby is down for naps.
The other half of his food portion can be fed in a stuffable puzzle toy like a Kong, Buster Cube or the like. This turns eating--normally a 20 second activity -into a 20 minute activity. He gets 20 minutes of mental activity and you don't have to lift a finger to make it happen.
If you are comfortable with the idea, see if a neighborhood friend could walk him for you to tire him out and give you a bit of a break. If you don't want someone to walk him or are worried that he will misbehave for them, have the friend push the baby while you walk Jethro.
Consider using two leashes--one hooked to the back of a harness and the other hooked to his collar. The one hooked to the collar will be the primary leash. Tether the one hooked to the harness to your waist. That way if he gets mouthy and starts pulling on the leash (probably a really fun activity in his mind) you can just drop that leash and end his fun. Once he realizes that the tugging behavior never results in a game of tug you should see it happening less and less.
If he really likes tug, teach him to play tug with rules and only ever play it with a special toy that you reserve just for that purpose. He should only get the toy if he sits and waits for you to offer it and he needs to let go of it when you cue him to. If he isn't at this stage yet, train a "drop it" and a "take it" to good reliability before beginning tug games. Tug can be a great way to tire a dog out and you don't have to go outside or travel anywhere to do it. Tug games give him an acceptable outlet for the behavior and give you a great game to use as a reward for other behaviors.
Don't let the one bad experience with a trainer prevent you from pursuing more basic training with Jethro. You can ask trainers for references, go observe classes that they hold, ask them about methods, etc.--all the same things you would ask of any service provider before you contract their services. If you don't like what you see, look elsewhere.
Good luck.