These 5 are a nice selection among the modern-vintage memovoxes (855 and upwards). You nailed a few iconic ones (black dial 855 and 2 tone 875 are as good as it gets in these references). A bit of funkyness with the 861, and a touch of late 60's class with the ebony too, which is echoed by the silver 875 (the most conservative choice back then in the line-up of memos on offer in the early 70's).
Now, you could branch out to more exotic dial choices for the classic 855 (lapiz, tortoise maybe), or to more extreme shapes in the 87x family (snowdrop, TV?), but at that point, I think you shoudl first explore the marvels from the hand-wound era, and try a few 489, 814, 910 and 911-powered beauties.
Memovoxes are like great wines. You can go horizontal (exploring all the options from a given era - like you have started here on the 855 and 916 calibers), or vertical (exploring all the variations over time of the classic foundation memovox).
You certainly did no mistakes in these five musketeers !