Hey Chrono, is there a way for a FirstPerson datablock and a ThirdPerson Datablock?
Yes, no matter which way you mean it.
By default, you can already switch between first person and third person on one datablock.
If you meant changing datablock when you press a certain button, or some other cause, where one is first and the other is third, then yes this is also possible, however not with the toggle third person view button.