Urgent Kitchen flooring question!!
1/2" plank subfloor? I doubt that very much.
You could have gotten away with 5/8" ply instead of 3/4", but the more plywood the better. You're gonna be about 5/8" higher, that's not a big deal and yes of course a tiled floor is usually higher than hardwood. A bevelled threshold or made as a ramp will cure that.
I suggest you consider using Ditra Membrane instead of cement backer. It'll save you a little height since it's 1/8" installed instead of about 5/16" for 1/4" backers.
BTW, please do not call "thin set" mortar "mud". Mud is a mix of sand and cement placed about 1-2" thick to create a firm base for tiles.
Tile 4 You LLC Troy, MI
KERDI Shower Specialist ... DITRA Installs ... Product-Method suitability consultation. I have NEVER made a mistake, I thought I did once...........but I was wrong! - PRODUCTS ADVERTISED WITHIN MY POST ARE NOT ENDORSED BY ME!