Oh, I was wondering why your desired layout had so many keys, especially in the first draft.
Have you already tried using such kind of layout. While you probably have some reasons behind your layout design, I wonder if it will work as well as you want in practice.
What kind of ergonomic keyboards have you tried so far ?
For example, in your first draft, that’s … a lot of keys 
Espeically those two lateral clusters have my pinkies screaming
The sub-sequent drafts also have a lot of keys, which is kind of defeats the purpose of an ergonomic ortho / columnar staggered layout in the first place.
Also, not sure if having different keys size as in the cluster below is comfortable to use:
From my personal experience, I went with an ergo mech keyboard with a relatively high number of keys, but getting used to layers has completely changed the way I view a keyboard, and I feel like you won’t need that much keys to be productive.
Looking forward to see how your project pans out, in any case.