I agree that the third photo is not A. argenticauda since it has multi-branched inflorescence. I have uploaded a higher res version of the third photo as a fourth photo. From this it is clear that the flowers are reddish (and not green). This implies that this is probably A. hereroensis rather than A. viridiflora since A. viridiflora has green to lemon-yellow flowers. A. viridiflora occurs closer to Windhoek. I will move photos 3 and 4 to a new observation as A. hereroensis.

The first two photos were taken of the same plant. I am fairly certain that is A. argenticauda. Note the dried remains of single spike-like inflorescences in the foreground of photo 1.

Thanks for the fourth photo and extra pixels. The flowers are not really open, but the buds look worryingly red. Perhaps this is just the widespread A. hereroensis with unmarked leaves.

Best wishes,