Also, can Telur be teleported?
Yes. Electromagnetic charges, gravity, the weak and strong nuclear forces, all of those can be teleported. Telur is no exception.
Yes, the prison planet can be used to house everyone's criminals. Yes, you can stay in orbit to drop explosives &c. down on them. I do, so why shouldn't everyone else?
Telar's flagships (a second one was finished about a year after the first one) go out into outer space. Their mission is to seek out resources for the Teleri Confederation, and to defend Hera against any hostiles out there. They don't go alone. Telar's first and second fleets go with them to provide additional support (cargo, firepower, &c.).