Before trading it is always wise to check the members review at The Rate and Review Forum. Make it your friend. To do a search there, use the Search Box found just below the list of threads on page 1. Here is a link that might be useful: Rate and Review Forum.

3. looks like Mammillaria geminispina ssp leucocentra to me (one I posted for ID a while back~but not positive on it). Link to one below. For Photobucket thumbnails, put a checkmark in the box (underneath) for the photo you want. Scroll down to bottom of page & click to select the generate HTML deal, then Go. On new page click on the 1st URL listed to highlight & then copy it (right click-copy). Come back to your post & paste it in. (That's the SHORT version of How To--think there might be instructions at the site somewhere.) ~Rosemarie Here is a link that might be useful:

Al, 40F is a minimum temperature typically used. My max/min in the garden has barely been that low so far this year. Some growers use 45F or even 50F, depends on what you're growing and how much money you've got to burn :) Toni-Marie, doesn't everyone have one of these? They're so easy to grow and propagate, mine drops pups if you say angry words to it. Larry, Mammillaria vetula ssp gracilis 'Arizona Snowcap' to give it the latest full name. Its a monstrose form of the regular M. gracilis, pups madly into a jumble of fuzzballs. It grows pretty fast, its incredibly tolerant of low light, overwatering, and this one came from B&Q, I think.

Tho cactus and succulents come from different continents, most require the same care. Fast, well draining soil with no peat moss, water in the summer months weekly. Air, Food after they are growing, shelter so they don't get wet the wrong time of year, from extreme cold below 40F and some need winter heat, + your love and care. Cactus can tolerate cold down to about 25F with out water for approx. 6 months, during their dormant period. Not all of these species are the same. This you will need to study and find out which is which. I know that Kalanchoe are more tender than the rest. Some can do just fine outside all year around here in Calif. All need very good light (bright shade)no matter winter or summer, some will need some protection, and some grow in the shade. The cactus can take as much light as you can give them but gradeually. They grow spines to protect themselves. Don't worry about the temperatures in the house, they like the same temperatrues that you do. Worry about the light and fast drainage during the winter. Let them dry out before watering again in the winter. These are very general instructions. I want to congratulate you on your excellent description on where you are growing them. If you put pictures up on this forum, the group will be able to identify most of them, and maybe the collection of houseplants as well.