The forum is quite quiet at the moment, but I'll have a go at your two plants, and hope that some others give their ideas as well.
#1 - I think it is Mammillaria karwinskiana ssp. nejapensis.
#2 - more of a problem, though it is, I think, a plant within the Crinita group of the Stylothelae. My first thought was perhaps M. zeilmanniana, but without flower colour being know, it is difficult to say. Has it flowered?