I wouldn't do 10 HPR going from 2 to 3, do 5 Stamina regen instead. If you're not sold on 5 Stamina regen, take a look at another pet that you're hunting with, and see if you are seeing the stamina drop and not go back to full. Doing 5 Stamina regen instead, I'd probably put the extra points into STR, but if you are just leveling off of crazy mage and allosaurus, it won't matter much, since you can make your 3 to 4 level in a day anyway.
For Resists, I would suggest 80 in PHY, Fire, Energy and the remaining Cold/Poison following whichever strategy you see fit. Pawain has been an advocate on Max 4 Resists, and he makes a good case. If you do that, you'll need to have an alternative pet for the low resist. But if you're good with that strategy, do the Pawain method. Hopefully he'll drop a comment on how he'd set them and how he'd train his alternate pet. My guess is that he'd have an overcapped Cu, which I think he actually already has with 80/80/85/40/80. Personally, I would do 80/80/60/65/80, but I can't make a strong case for where the 60 should go either way.
Definitely, train up 3 to be ready for 4, but you'll need to decide on magic type at that point, necromage, chiv, or leave it natural. If you are going to use an entire level to do necromage, it's a lot of work, but definitely do a post patch first and let it get skilled up before you decide if it's for you. Also, don't leave it to 4 to 5, because you won't be able to max base damage if you do that. It's an irreplaceable pet, so take your time so you don't regret a mistake or a template you don't enjoy. I've seen a noticeable jump in how the pet performs when Chiv gets over 80 as well. So that might be one to also do on a post patch pet first, to see how you like it.
Glad you are porting your guy over to test center to experiment to be careful, and I hope you enjoy your final pet.