Good to know you are willing to use a more appropriate container.
So first to analyze the growth habit of those succulents there, Senecio rowleyanus is more of a trailing, downward growing plant, so it is better to be in a hanging container. The other two are more upright growing ones, so you can still put them all in one container, try to center the upright growing ones and put the trailing ones to the sides. Just make sure container you use have drain holes. It can be plastic, ceramic or clay, although clay is better for succulents since it is more porous and easier to dry out the root zone.
As for the media or soil, use cactus/succulent soil and you can add some more perlite or pumice to make it more open, so it will not compact too much in the container and keep it really well draining. Succulent roots are very shallow, so you do not need very deep containers, and most are slow growing so not too big a container.
Putting them in a smaller planter for now will be better, since the plants are still very young, and as you said, it will be easier to move them indoors if needed. As long as the soil is well draining, even it it rains, it should not be a problem. It will be a problem if it is cold winter rain and temps continue to be cold, succulents do not like soaking in that too much. But like any other plants, they like rain, as long as their roots get to dry out fast. Be mindful of the temperature outside, if it is still going below 40's there, better to keep them indoors by your sunniest window, the plants are still too young.
Good luck, and hope you can propagate more!
