You are spending needlessly.
The SLX's: if you havent tried them on and only came to this conclusion on price, stop. Go try on a bunch of stuff from as many brands as you can, pick what fits best.
Diodes: definitely not beginner friendly. Look into the Genesis. Still "techy" and a great binding, but more forgiving.
Boards: there is no reason to buy a Method or Mystery unless you just have to have the most expensive shit you can. That is the only thing they do best, putting holes in a wallet. For boards look into boards like the Flow Drifter, K2 Turbo Dream, Ride Berzerker, Bataleon Goliath, Salomon Grip, Signal OG Flat, or Yes Basic. All of those will inspire confidence while you're learning, and none will hold you back as you get better. They're all boards a seasoned rider would pick.