LOL, Love the way you said (I am beginning to imagine what parenthood is like).. !! LOL, Yup i agree! And i now say anyone who is thinking of having a baby, should get a puppy first and see how they cope before they bring a human child into this world, my puppy has taught me so much more patients (& i thought i was pretty good before)
I wouldnt be submitting him, other dogs do not force each other to the ground, it mean little more than you smacking him, i am not surprised he was afraid. I would be to if someone 10 times bigger than me forced me down and held me there. This can also make him more aggressive with other dogs, as he can learn, if he becomes uneasy to bite (Out of fear), as you had given him no other option in the past by using the submission. Usually a dog will growl to let the other dog to back off, by submitting him you are pretty much taking this option away from him full stop, teaching him the first thing to do, is to bite without a warning growl. Just try to ignore him (no eye contact even) and if he kept up, 1 minute timeout (But no longer than 1 minute, or he will forget what he was in timeout for in the first place)
Have you thought about getting him a puppy pen? you can put his crate/bed in the pen so he can have a sleep when he wants, but can also leave some toys like a stuffed toy, a treat ball or kong with some goodies to keep him entertained, a puppy chew bone (Like that busy buddies or nylabones) for him to chomp on if he is bored. That way I think you wont feel so bad about leaving him all day while your at work
Try also putting a blanket over his crate so its warm and dark, like his own little den really. He might feel more inclined to go to sleep at bedtime rather than keeping you awake all night, little rat bag!
Oh and know, Leo hates being groomed! i am still working on this with him myself (10 months old) so dont stress, lots to learn, just try little by little each day. He is now much better with bathtimes, Hates them but doesnt struggle and kick up a huge fuss anymore (I did this by getting him to drink from the shower sprayer nossle i attach to the tap, as he loved drinking running water and made kinda a game of it so i feel it helped) and lots of praise and cuddles for being a good boy in the bath. He now actually climbs into the bath by himself so lick the shower sprayer nossle! ahaha! And will let me look in his mouth after much practice, but no brushing yet, wont take that yet! LOL
Sorry, again i ramble, but just trying to through ideas out there which may help