Its been a few days and you haven't had any replies, so I will try to help. I am not certain about any of them, but......
#1 looks like a rather tall form of M. rhodantha, quite a long spined form, if it is.
#2 might be M. bocensis, but I am by no means certain.
#3 is one of the karwinskiana group, but I am not sure which, the photo isn't great.
#4 looks like one of the forms of M. rekoi, a very variable species
#5 might be M. hahniana
Don't take these suggestions as correct, more as a starting point. Flowers would be helpful.