I work at a LFS, so I can at least tell you how WE get colonies shipped to us.
Odd as it sounds, zoanthids are shipped without water, but are covered in wet newspaper. This saves money on the weight of the package, and I've never seen zoanthids not open from this method the next day.
For the monti, get yourself a piece of Styrofoam and rubberbands. Rubberband the colony by whatever its attached to (rock, plug, disk, etc) to the Styrofoam, and place the colony downside in a bag of water. The Styrofoam will keep it floating, keeping it from rubbing on the bag or smashing into the container.
Triple bag what you are shipping, and snag a Styrofoam box from your LFS. We give ours away, we have them coming out of our ears because we get them with every order. Ball up some newspaper to fill the empty space in the styro, and volia! They're ready for their adventure.