I prefer any kind of grooming spray to water because it helps keep Sundance fresh longer between baths. It doesn't have to be fragranced or anything, although I don't mind as long if it's light and I like the smell. It's the other ingredients that seem to make the difference. I'm kind of a product junkie so I end up with a lot of grooming sprays. Very few have been awful, but Ice on Ice is the best and it's also the best value. I usually fill a bottle with 3/4 Ice on Ice solution and then I mix in 1/4 of a grooming spray that is just okay, in order to use it up. A lot of grooming sprays have strong fragrance but diluted they're a lot better. I also sometimes add a bit of diluted human conditioner, depending on what I have. It's usually a very impulsive mixture

I used to keep track in case something was really great but now it's more like, a little of this, a little of that, completely based on whim. It honestly works just the same.
I think the type of brushes people prefer have a lot to do with how people use them, and the individual coat. For a puppy I really think a wooden pin brush is useful. My puppy adapted to being brushed with the wooden pin brush much more quickly than he did with the comb or other brushes, so it was really helpful in training and increasing grooming time. I also used it a lot in the winter and when he was blowing coat, not to replace combing but to add quick 30 second brush outs, like around his harness after a walk. As you figure out how often you want to groom, the length you'll keep your Hav, and how much of it you want to do yourself, I think that's a better time to invest in additional brushes. When he starts blowing coat around a year old a wire brush might be helpful because I think it captures loose hair better.
I did use a slicker more often at one point and I liked it when he was short but I don't see it as essential at all. The problem I have with slickers is the ones that are soft enough start to bend so they are only useful in certain situations. It's also easier to damage the coat. I still have one but it's in my "overflow" bin and I rarely use it.
One newer brush development for me is the Ice Slip brush. I finally bought it, and I really like it! It doesn't replace a comb, but it comes close. The CC wire pin brush works well for blow drying, because it gives more of a fluffy feel and captures a bit more hair, but if I had to choose I feel like the Ice Slip brush works almost as well for blow drying and is more versatile over all because the pins are a bit more firm.