Kansai

A 2 1/2" BC 10 years old in the wild would probably be 10'-15' tall with, as you said, the heavy branching toward the top. BCs backbud like crazy so you shouldn't have any problem developing new branches provided the tree is in good condition. I'm not sure about bare rooting BC at this time of year, but I would pot it up in regular potting soil and keep it good and watered. I also probably wouldn't take any new growth off until winter. I would also make sure that the chop is at a sharp angle and dressed with pruning paste.

As far as multiple branches go--here again I wouldn't cut anything that's green. Of course a photo would help. I would just pot it up and let it reestablish itself. And again I would put it in a big roomy standard pot with regular potting soil while it developes the branch structure you're looking for. Next year you can trim it up and then stay as busy as you want rubbing new sprouting buds off the trunk.

Sounds like you're shooting for a flat-top. Bald cypress are great trees. Good luck with yours.
DR