Regarding Neo Zeon's MS development, this does seem to put the final nail on the coffin of the theory of the Zaku III competing against the Dooben Wolf late in the war for becoming Neo Zeon's next mainstay MS. As suggested by the pressence of Zaku III units on Dakar, the design was most likely completed and deployed around the same time as the Dreissen, whose first unit belonged to the forces that participated on the same descent operation.
I do find odd that we only see about 8 Zaku IIII units, including Mashymere's, during the course of the series. The above mentioned context would indicate that the Zaku III should ahve been produced in numbers at least as large as the Dreissen's original production run, which should include the Dreissens we see before and during the ground arc (about 16 units), as it was originally meant to be mainly used on Earth. Maybe the Zaku III was the opposite case and mainly deployed on space sometime after Haman departed to Earth, justifying its low numbers on screen.
As for the Dreissen's beam bazooka, while the design do seems to be quite similiar to the one used by the Dwadge Reinforcement Type, the background of the later doesn't seem to provide an explanation on how the designed ended on the hands of Earth-bound Zeon remnants.
Should we assume that Axis did mantain contact with the Zeon remnants and actually provided them technology? If so, the Desert Zaku upgrade used by all Zeon remnants and anti-Federation guerillas might have been provided by Axis (providing a convincing explanation on how all those groups ended up with the same design).
Then there's the Dwadge Reinforcement type itself. I have thought about this before: could this unit also be a design provided by Axis? Wouldn't it basically be the ground equivalent of the ReGelg: an improved version of a OYW model, with additional mobility provided by the extra thrusters on its shoulders. Its color seems to be a big hint as well as both units
use similiar colors
, which by the way, does not match Rommel's previous personal unit's color
Considering all these ideas, this is my idea of how Neo Zeon's original MS development plan was supposed to look like:
-Gaza-E (intended for atmosphere use as SFS?)
-Jamru Fin (incomplete MA completed with substitute components)
-ReGelg (updated Gelgoog)
-Zaku III (Zaku HMT successor)
-Dreissen (Dom/Dwadge successor)
-Dwadge Reinforcement Type (updated Dwadge)
-Shamblo (design completed, but not built)
-Qubeley Mark I/Mark II
The Dooben-Wolf, Geymalk and Queen Mansa would be developed after Neo Zeon captured and analyzed the Gundam Mk V and the Psycho Gundam Mk II.