As for your board choices, Customs are nice but there is a lot of tech out there for less money. If you want it, buy it. You could grab ANYTHING new and notice a huge improvement over a 12 year old deck. If you want an all round board I personally like the looks of Never Summers SL-R and Evo-R. The rocker is very light on it, rocker is fun, but imo it's sketchy landing kickers with. Both those boards are amazing for the money, but buy what you like. I ride a Signal Park Series and it's currently my favorite board of all time. It's super light and very flexible. It's great for everything but really fast grommers. Get what you like, don't blow the bank, but do a little research and grab something you like. Venture past Burton's website and check out Bataleon, Never Summer, Signal, Venture, Ride, Rome and whatever you can find. Don't let the new tech overwhelm you either. Just note that if you want something for all conditions don't go with "too much" rocker, I'd say keep it under 5mm.
If you're using that Frosty size calculator, it's pretty good. Anything else I've seen is a crock of shit. One tip is that height is almost not a factor at all. Also, with any calculator use your judgement and go with what you're comfortable with. If you had control and stability on that 156 get something similar. 10cm is a huge transition, and will have a learning curve. I wouldn't jump more than 5cm for the same conditions unless you gained like 35lbs or more. If you still ride the 156cm and you like it, get something 156-159 and you'll be fine as long as your feet fit on it.
I don't know a whole lot about goggles because I rarely wear them. But I wouldn't bother will polarized if you need to be seeing that ice. Yellow, Orange and Brown lens cut glare just fine. I usually wear RayBan driving series Aviators or nothing at all. If you ride around a tonne of rocks I don't recommend wearing glass lensed sun glasses though.
Anyway, that's my two cents. Feel free to ask me, or us, anything else you need. There are some really good "stickies" on fitting boots and board maintenance that are worth a read too. Peace man.