I was just about to make my final changes, but after seeing your update, I had to test it first :-))

Very good interim result.

Sticky Navigation on Desktop

I think that's very good. In the past, I have often had to scroll all the way up again to select a different navigation point. Alternatively, I would have suggested a "scroll top button". But the sticky navigation is a better solution.
The button would be useful in the mobile version.

What else I have noticed:

• The navigation bar does not contain any icons (when not logged in), whereas the icons are displayed in the navigation after logging in. The icons are currently only visible under "My Profile".
• In the navigation bar (not logged in) under "My Profile" it only shows "Wallet". It should probably be 'My Wallet' here.
• When I open a post from your blog, the navigation still contains "@the-gorilla". Even if a post by another author is opened. Is that how it should be? I would intuitively expect informations from the author or alternatively informations from the logged-in user.
• When I open a link with copy+paste in the address bar, the navigation bar appears in a shortened version without the user name. This is probably the result of the memory problem described in your previous post.

Everything should work smoothly

Absolutely! Very good!

I'm nearing the point where I can submit this implementation to GitHub

Do I understand correctly: You want to make a PR for the Condenser for this interim status regarding the navigation?
We should agree on this, as I would also like to submit a PR after a few changes in the Condenser. However, the frontend would only be the second step for me, as Hivemind has to be migrated by the Steemit team first. Of course, I don't know how long this will take.