Here comes to the prime lens test.

Is 200mm "sharper" than 50mm? Is yes, by how much degree?

In these two crops, I could conclude that 200mm is "sharper" than 50mm, but the most important point we should pay attention to is that by how much degree 200mm is sharper than 50mm.

I agree that the increase in sharpness is due to the following reasons:
(1) longer focal length (200mm vs 50mm)
(2) better optics (L lens vs non-L lens)

The point is on whether item (1) or item (2) contribute more to "the increase in sharpness". In my opinion, item (2) is obvious to contribute more than item (1).

So let's back to the question - is Minilux "sharper" than TC-1?

Yes, because it has a 40mm lens, but TC-1 only has 28mm lens.

However, is this a major factor contributing to the difference in per-pixel sharpness between the two cameras?

I don't think so.

Do judge by yourself and compare it with the Tamron lens comparison (24mm vs 50mm) before you derive your conclusion.