You can take more than one unit of TG. If there is a slann, you can choose which unit the slann goes into. The slann cannot leave the unit though.
Chameleons:
Deploy them after all other deployments have been made. The deployment of scouts occurs after heroes. This makes it after the normal deployment. Since the deployement in complete before scouts are placed, scouts do not count toward the last unit deployed and the 1+ for finishing deployement first.
Now, when you deploy the scouts, Chameleons can can be placed anywhere on the board as long as they are 12 inches away from any enemy unit.
If you have any other questions, let us know.
Hope this helps.