Up to date there are 5: Woodwinds, Brass, Strings, percussion, and electronic.
Four.
Strings, winds, brass, percussion.
The Ukulele Orchestra of Great Britain uses them exclusively. Many Hawaiian groups concentrate on the ukulele.
four
His family
Usually there are no baritones in an orchestra.
it depends on the orchestra
There are usually no mandolins in an orchestra.
London Symphony Orchestra Philharmonia Orchestra Royal Philharmonic Orchestra The Halle Orchestra and maybe many others
There are usually 40 to 60 performers in an orchestra.
There are about three to four trumpet players in an orchestra.
In a typical orchestra, zero. None.