Can I use these bindings?

So
I'm 19, I've been snowboarding the last 4-5 years but, tried skiing last year on a pair of my friend's snowskates and I got hooked on skiing. I wouldn't say that I'm advanced or expert on skiis (depends on if you determine that by speed or by ability to travel through trees) but, I can go through trees, powder, diamond runs, you name it, I'll run it.
So, I invested into a pair of K2 press 2017 ski and these are the dimensions:
Tip - 113
Waist - 85
Tail - 104
My body:
Height - 5'8 - 5'9 (176 - 179cm)
Weight - 135-140 (and bulking and weight lifting, so probably by the season, I'll be 150)
Boot size - 8 (26 for mondopoint)
The main question being that I found these two pairs of bindings on ebay I wanted to get. The problem is one is 120mm wide in the brake and the other are Jr. bindings and the DIN maxes out at 4.5.
So I was wondering if I went with the 120mm, could I replace the brakes with a 90-95 mm brake?
And for the Jr. Binding, with my body weight/height, could I use those bindings? I don't do much park at all but would be riding switch, diamonds, work on jumps, etc. All mountain basically. Any info helps! Thanks :)
http://www.ebay.com/itm/NEW-W-O-Packaging-Rossignol-Axial-2-bindings/222581749035?_trksid=p2481888.c100675.m4236&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D04ae3e92a8fc42d0a66d6d96deac0813%26pid%3D100675%26rk%3D1%26rkt%3D15%26sd%3D222581749035&_trkparms=pageci%253A7e23699e-6ff5-11e7-965f-74dbd1804e20%257Cparentrq%253A718bf1e415d0a866a472ed06ffffa681%257Ciid%253A1

http://www.ebay.com/itm/Tyrolia-SX-4-5-AC-Brake-74-K-solid-red-black/332314842464?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649