Any issues about him being stressed about being left alone have seem to have dissipated. He goes to his room quietly and calmly, and will run right in the room when I say "Time for bed!", when I go to work or when it is actually bedtime. No more whining or barking, and he doesn't stir until we get up in the morning. He has had two nights of snuggling up in bed with us while we watched TV, but he is still sleeping in his own room at night.
He's settled right down with the eating pattern, and he's now eating in the kitchen, two meals per day, along with my other three dogs. We are working on his sit/stay during feeding time while I set down his dish and he waits patiently for his release word. His targeting and down behaviours are coming along nicely as well, and he's started to gain a bit of interest in puzzle toys, although he clearly doesn't *get* them. He'll eat the treats that come out, but doesn't really get the concept of pushing them around to work for his food.
I've been taking him outside to play along with Gaci and the ball. Gaci's not much of a ball player, but she loves the chase, so we've been playing games where he catches and brings back the ball, and Gaci races him down and back. In the beginning he was a bit guarded, and guard-y, of the ball with her, but he's beginning to understand that she's just having fun running with him, and doesn't want the ball. He's taking a bit of a rest though for a few days since he seems to have overexerted himself a bit and was tender on one leg after playing. I'm guessing he just jumped a little too much or stepped into a little rut in the ground, but all is well, just needs a little rest for a couple of days.
He had his first haircut with me this past week too, as he was pretty scruffy! And he was just the most perfect guy, didn't flinch at all and stood nicely the entire time I clipped, combed, and scissored him. The next task to tackle will be his nails, as they are quite long, but I figured that was enough for one day for a new challenge. Baby steps!
He really is developing into the most affectionate, sweet little guy. He loves his rubbies and he loves his snuggles, and is just looking for a little dose of attention here and there without asking for too much. And of course, he loves his ball!
A couple of photos of him and Gaci playing (30 foot line attached). He is the one who always has the ball in the photos.