His weight seems to be about right. Every pup is different, but the general rule of thumb is around 10 lbs/mo of weigh gain for the first few months. Just going by what he weighs isn't a good method, although it's a factor in determining how healthy his weight is.
What is also important is the quality of the food you feed. Most Newf people say skip the puppy food, but go for high quality adult food. Slows their growth, which is important to their structural health.
The best test of weight is to feel their ribs. You just want to feel a little flesh over them, but still be able to detect them. If you feel big spaces in between ribs or you can see his hip bones protruding, he's probably underweight. If you can't feel ribs or see a slight waist on him, he's probably too fat. If you're not sure, ask his vet.
When he's young, weight gain can fluctuate wildly. If you record his weight weekly, you'll probably see that fluctuation. One week he could gain 4 or 5 lbs, and the next only 2 lbs, then 3 and so on. It won't be exactly the same each week. But don't let slower growth fool you into feeding more. It's liable to pick up and taper off again for several months until stabilizing. Remember too, that he won't be finished growing until he's at least 2 or 3 years old. After about a year old, the growth rate slows down considerably and when he's around 2 or so, he will start to fill out in his rib cage. So expect him to look scrawny until he starts to mature.
So don't think you have to worry about his weight right now. Pups are notorious for conning owners into overfeeding. Stay strong and resist his sweet pleas for more food. I think it's better to err on the side of underfeeding a bit than overfeeding.
Don't be surprised if he starts refusing food in a couple of months. My pups, around 7 months of age, decided that they weren't all that interested in food anymore and became somewhat finicky and turning their noses up or just not finishing their food. That, to me, was an indication that they didn't need as much, so that's about the time that I started cutting back to twice a day. If they leave food in the dish after 15-20 minutes, I pick up the dish and then they don't get fed until the next scheduled feeding. One went from 6 cups/day to 4 to 2 and another from 4 cups down to 2. Each dog is different, so keep that in mind. Some need more than 2 cups per day. Just keep feeling those ribs.
As for the counter surfing, be meticulous NOW about keeping your counters cleared of everything. Even utensils. Hopefully, he will learn that there is nothing of interest up there and quit looking. Be vigilant about supervising him or baricade him from the kitchen if possible. Every time he is successful at practicing counter surfng, he is reinforcing the behavior, so you MUST not allow it to happen ever. If you can't supervise, then crate him, especially when you prepare meals. All it takes is a nanosecond of turning your back for him to sneak up there. If you see is is thinking about it, redirect him to a favorite toy, activity or treat. Do it before his front feet leave the ground.
That being said, I had one who was so sneaky that he rarely got caught and was a surfer the rest of his life. My fault for not trying harder. None of my other dogs were counter surfers, but he was my first Newf, so beginner's mistakes.
