As far as color you want some opaque and translucent options. Translucent for clear water and opaque for water with some color. Keep it simple. You really just need the belly to be white, clear, or black. The fish will see the sides of the bait a little. The action is what's calling them in way more than the color.
All of your gear options will work. Mono is probably the best option for topwater since it floats and will allow the lure to work freely. Braid also floats but is so limp that it can often get wrapped around the trebles and ruin your cast. Another con of braid is that it has no stretch which I want when using treble hooks. I prefer casting gear when standing on the deck of a boat, but I usually prefer spinning gear when in my kayak or wading. Basically when I'm standing and can twitch the rod downward or slightly to the side I prefer casting gear. When i'm sitting or standing waist deep in water I often have to twitch my rod tip up or to the side and spinning gear makes this easier. Just a preferance.
I throw either 10 or 12 lb P-Line CX Premium on casting gear and 8 lb on spinning gear for all treble hooked topwaters. For larger walking baits i throw 15 lb on casting gear.
One last thing, I always use a clip or split ring on my walking baits. Allows the bait to move freely side to side. Hope this helps!