It seems worthwhile to also keep in mind other quantum mechanical degrees of freedom, such as spin

Only if the spin's basis turns out to be relevant in the final ToEILEL (Theory of Everything Including Laboratory Experimental Results) that gives a mechanical algorithm for what probabilities I anticipate.

In contrast, if someone had a demonstrably-correct theory that could tell you the macroscopic position of everything I see, but doesn't tell you the spin or (directly) the spatial or angular momentum, then the QM Measurement Problem would still be marked "completely solved". In such a position-basis theory, the answer to any question about spin would be "Mu, it only matters if it affects the position of my macroscopic readout."