About water, you are correct to be cautious, but this is not a cactus. If the soil is dried out then moisten it conservatively. Not so much that water comes out the bottom, but enough that the water soaks down into the soil. This plant may have almost no roots, which is OK. But it it will need to grow new roots and get established, and moisture will help out with that. But go ahead and let it dry out between the occasional waterings. Too much water is more often the problem than not enough.
