an incumbent
The person who is in office and seeking re-election is the incumbant electee. If he is likely to get re-elected, he is called a shoo-in.
No federal official can be removed in this manner. However in some states this can occur in what is called a recall.
If enough signatures are on the petition, there will be a recall election in which the public can vote to remove a public official from office.
no
To Impeach
empeachment
a formal document charging a public official with misconduct in office
The question is somewhat unclear. You could be referring to Impeachment, or you might be referring to Misfeasanceor Malfeasance in office.
The outgoing official is called a lame duck. The period of time this official is still in office is called the lame duck period.
an incumbent
candidates?
civil servant
A "Recall" is a process in many areas where an elected official can be removed from office by the voters.
nomination
It's Yamen(衙门)。
The vote is called "recall"