Just bought a '17 Chevy Silverado 1500

What can people tell me about Equalizer Weight Distribution hitch? I was told it takes weight off the tongue. Is this true?

No. It removes load from the truck's rear axle, and moves it to the truck's front axle, and some is transferred to the trailer axles. But it does not remove tongue weight, or change it. It is still there, and counts as payload. The idea of the WD hitch is to level the truck/trailer combo out and return the front end to it's unloaded ride height for better steering and handling. You will need one with the Grey Wolf. Yes, the amount of load transferred to the trailer can be deducted from the load on the truck, but the only way to know that number is a trip to the scales with the trailer hitched up.

Dealers have a reputation for telling customers they can pull anything with whatever truck they have. Even at a good dealer, RV salespeople are usually not technicians, and generally know little about tow vehicles and proper hitch setup. Some aren't even RVers. It's easy to say hairs are being split when they aren't the one who has to deal with the rig in heavy traffic, high winds, bad weather, etc. You'll get better advice from the knowledgeable and experienced RVers here.

There are people who say you need an HD truck to pull anything with two axles, and people who will say the manufacturer's numbers are artificially low because lawyers, and to go ahead and pull a 36' 5th wheel with a Tacoma. In between those extremes you'll find the answers to your questions. I've towed over weight and with less than optimal setups, and it's no fun. Myself, I think the Grey Wolf and that truck with your family will be OK. Not awesome, but OK.