Between Poland and Belarus.
John Forrest didn't discover Australia. (Nor did Captain Cook, a commonly believed myth.) John Forrest was an Australian explorer from Western Australia. He also became the first Premier of Western Australia. For details on who actually discovered Australia, see the related question.
Alexander Forrest was an explorer and surveyor of Western Australia. Like his famous brother John, he explored and charted unknown regions of the western state. Travelling with his brother John in 1874, Alexander departed Geraldton and discovered the Weld River and the pastureland land around it. In 1879 Alexander Forrest led an expedition from the DeGrey River north to Beagle Bay, then headed east inland into the area which is now known as the Kimberley. On this journey, he discovered the Fitzroy River.
Forrest Sr. was introduced to Forrest Jr. at Jenny's apartment in Savannah, Georgia.
Yes. Although both brothers explored extensively with their own crew, they did undertake one exploration together. In 1874, John and Alexander Forrest travelled together, departed from Geraldton, and discovered the Weld River and the pastureland land around it.
No
William Forrest Andrews, known as Steve Forrest, was not a descendant of Nathan Bedford Forrest or his brothers. He was actually the great-grandson of Nathan Bedford Forrest's brother, John. The family connection comes through the lineage of John Forrest rather than Nathan himself.
Forrest Seabury's birth name is Seabury, Sumner Forrest.
Forrest Sherman's birth name is Sherman, Forrest Percival.
Forrest Tucker's birth name is Forrest Meredith Tucker.
Forrest Burns's birth name is Forrest G. Burns.
Allan Forrest's birth name is Fisher, Allan Forrest.