Help with Cactus ID

[otusasiotours]

Hi,

For many years I've been interested in having a cactus collection and over the past 2 months have finally acted and have purchased about 20-25 plants. Many of these have been ordered online, so in those cases I know what I am getting. However, some have come from local greenhouses and were labeled simply "succulent." If anyone is willing to look at a few pictures and help me with genus & species info and some cultural tips I would really appreciate it. I realize it is difficult to ID plants that are not flowering, but I'm thinking these are probably all pretty common in cultivation or they wouldn't be for sale at the local nursery. The first pic is attached.

[teo]

A monstrose cactus - maybe Cereus peruvianus

[nbcrty]

i believe this plant is known as a 'mini'/ cereus preuvianus monstrose cv.
i named my C. preuvianus monstrose, Brock... because he reminded me of broccoli...

[martenfisher]

Cereus forbessi ' Ming Thing ' pretty sure it is not ' Mini ' or peruvianus. I needed I can show side by side since I have about 6 different form and several different species of monstrose Cereus.