Impossible to say, as "them" isn't specific enough to give an answer.
The band and the orchestra played together.
The orchestra played wonderful music in the theatre.
My uncle Wilbur plays in an orchestra.
The London Symphony Orchestra
The London Symphony Orchestra
Tuesday I went to a performance of the Chicago philharmonic orchestra.
No.
The name of a device used to conduct an orchestra is a baton.
Generally, this is called a "string orchestra" although it could be anything.
A conductor leads the orchestra with a baton.
For pieces that use it, they only use one.
Yes, picollo's are used in full-sized orchestras, the London Symphony Orchestra use them in their performances. In fact, every orchestra uses one or more piccolo when the music requires this.