I think you are right, mmartin, with the species for #1.
Having thought about for a good while, and checked various books, photos, my own plants etc., my best suggestion is M. vergelensis, which is a form of M. nana. It has quite tight spination, more so than many forms, and its flowers can be paler than the usual yellow of M. nana. I have one plant of M. tricacantha and that seems a bit more open than the plant shown. But that could just be my conditions. northern light levels.
When I blow up your photo, the plumose radial spines suddenly become obvious, which is a bit of a give away. I should have done that before!