OK, and hello. I'll have a go at your quiz?
#1 is M. geminispina
#2 - if it is a Mamm, then it might be related to haniana. Does it have axils? I can't see in you rphoto.
#3 is M. polythele.
#4 looks like one of the M. spinosissima forms, but not sure which.
#1 I don't immediately recognise, I'd like to see it from the side and also know if the flowers are red/pink as they suggest.
#2 is a form of M. magnimamma, such a variable species, but its a bit young yet to try to add a form name.