Really? Because the one thing I've heard about a million times is don't put tile on plywood...
Okay then you do what you think is best, forget about me.
I will tell you that tile has been installed successfully over plywood since plywood began. The problem is...better methods are now available and installing tile over plywood being done by idiots that cheap out is problematic.
If you do it like I have suggested you'll be fine assuming the correct plywood is used and the correct thinset mixing method I suggested is used.
I'm not here to argue about it, you do what you think is best. You are the one that wanted to hold the tile elevation to a minimum. This is how you do it.
My advice is to use backerboard but you are the one that has already poo-poohed that idea.