Lactose intolerance is an issue for some people, including me. Otherwise, I would be drinking milk all day long.
You know who is 5' 7" and at 170 lbs competition weight? Lü Xiaojun
Edit: In my opinion, you will need to get fat to put on the muscle. It's just how the body works. So at one point you'll need to put in those extra calories. IMO the best time is July, August, bulk until Feb, March, and start a cut. Assuming you'll want to be shirtless in the summer
I've been lifting on and off for about 20 years, and no where near the physique of the dudes here. My advice should be taken as a grain of salt.
I was also on a 1500 calorie cut last year, it was horrible. Athletic performance across the board was down, couldn't lift as heavy, run as fast, or for as long, and I was super grumpy all the time, straight hating for no reason, lol. Started eating about 2500-2800 calories again this Jan, huge difference. Back on track on lifting heavier, and a personal best/record for 10km run. For a month, every time I ate till I was full, I could feel the dopamine rushing into my brain. My stats are 5' 7", about 175 lbs, 16% bf, ball park. I try to keep my macros at 40% protein, 40% carbs, 20% fats (unsaturated if I can help it). I also try to stay away from high glycemic index foods, pretty much no refined sugars, the only sources I have are from my protein bars, and Gatorade.