I have 3 plants, Gasteria, Haworthia and one cactus, the Euphorbia enopla. I have the appropriate soil with drainage but I was told the cactus would not do well with the others. How would I go about putting them in the same pot? Could I put the cactus in a small pot and plant the other two in a big pot?
All of these succulents are from a similar environment in Southern Africa. If you put them in a nice big/long pot and don't over water, they should co-exist. You can mix diverse species using some tricks, I place the cactus in their own terra-cotta small pot and bury it in the bigger pot and create a soil micro-climate. I then water that part less, but if the dirt drains well, you shouldn't have a problem anyway. All these plants are low water, but not dessert-like, a little water bi-weekly (2 weeks).
I have lost 2 Haworthia attenuata from under-watering them in a cactus pot once, but I think the soil was too sandy for it. I have had another one by itself for decades.