Yes, #2 and #3 are Mammillarias, I'm not positive which. #4 is Echinocactus grusonii, very much a baby still. #5, Pachypodium? Someone will know this for sure. #6 is a Stenocactus, very hard to tell the different species apart. #7 is Frithia pulchra. #8 is Mammillaria carmenae.

The 1st is Mammillaria candida and the 2nd I don't know. The offsets of the Gymno can be taken off and rooted. But I would give them one more growing season to let them become bigger. I wouldn't mix them with even small Aloes. Because I think the Aloes need more water (and to a different time) than the cacti. Jordi

Did you mention where you live? (Good idea is to put general location and/or growing zone next to your name...) Yes, Sempervivums could be grown indoors but usually they don't look their best. I am not sure if they are better off with having to spend winter outside (some plants have to have x number of cold days to grow well); unless you get them really good light during winter they usually look quite sad. During summer it may not make that much difference. But amount of light is always less indoors than outdoors. But if you don't have access to garden or deck-balcony, you have to just do it indoors. Many ppl have to, living in apartments without balcony or any other outdoor space. All of the succulents need lots of light otherwise they stretch as I already mentioned about Painted lady. I use lots of supplemental lighting in winter, and probably will improve even more next winter. here is same Echeveria purpusorum, still indoors (March) and blooming, under lights: Adding more perlite definitely helps.

Sadly, just because a bagged soil is called 'cactus soil' that doesn't necessarily mean it's any good for cacti and succulents as we've said many times before, it's just sales blurb. They will die in that mix whatever their size, large or small, the result will be the same. Can't tell what the planter/s look like size wise in relation to the plants or whether it's one big planter, but whichever, there's way too much unused 'peaty' type compost. It will cause one of two things to happen...if you water thoroughly which they will need (but they also need to drain properly) it will stay wet and they'll rot. Failing that, the soil may become hydrophobic, you will think you are watering it but it will stay dry at the roots, as spray bottles don't water efficiently. Please do a search for a more suitable mix using the search box a the top, your plants will thank you in the end. Gill