He's going to be a big lad! Watch those dew claws, they can be awkward on bigger dogs. Personally, I'd have him neutered at a suitable age and the dew claws taken off at the same time. Ted suffered a DIY job with his previous owner and the resultant 'sprouting' of claw was a ballache until we had them removed.
Puppy classes is a very good idea, as is socialisation with other dogs every day on his walks. You don't have to go over the top with the pack order thing, it's easy to do without being bonkers about it.
I know I've suggested this many times on dog threads here, but google for Nothing In Life Is Free (NILIF). The general principles are a great foundation for a puppy (or an adult rescue) and worked wonders for our Ted.
There's nothing worse than a dog that doesn't want to be pack leader but is forced in to the role by it's owner not assuming the position. Good luck with him, and well done for going down the rescue route. Beautiful pup.