Of the three the President of the European Parliament is the one whose notion of dismissal is more vague. There is a description about its election in the Article 14 of the Treaty of Lisbon but not for dismissal:
- The European Parliament shall elect its President and its officers from among its members.
In any case the President of the European Parliament is a member of Parliament and consequentially is subject to the Rules of Procedure of the European Parliament. This means any member of the parliament can be suspended (it hasn't happened to a president, but the suspension of an MEP is not without precedent). Also notice that the powers of the President of the European Parliament are not comparable to the other two you've mentioned.
For the Presidency of the European Council the European Council is responsible for both appointment and dismissal as is described in the Article 15 of the Treaty of Lisbon:
- The European Council shall elect its President, by a qualified majority, for a term of two and a half years, renewable once. In the
event of an impediment or serious misconduct, the European Council can
end the President's term of office in accordance with the same
procedure.
The President of the Commission responds to the European Parliament which can remove the President of the EU commission (in fact the whole of the Commission) by a motion of censure as is described in the Article 234 of the Consolidated version of the Treaty on the Functioning of the European Union:
If a motion of censure on the activities of the Commission is tabled
before it, the European Parliament shall not vote thereon until at
least three days after the motion has been tabled and only by open
vote.
If the motion of censure is carried by a two-thirds majority of the
votes cast, representing a majority of the component Members of the
European Parliament, the members of the Commission shall resign as a
body and the High Representative of the Union for Foreign Affairs and
Security Policy shall resign from duties that he or she carries out in
the Commission. They shall remain in office and continue to deal with
current business until they are replaced in accordance with Article 17
of the Treaty on European Union. In this case, the term of office of
the members of the Commission appointed to replace them shall expire
on the date on which the term of office of the members of the
Commission obliged to resign as a body would have expired.
This is also described in the Article 17 of the Treaty of Lisbon:
- The Commission, as a body, shall be responsible to the European Parliament. In accordance with Article 201 of the Treaty on the
Functioning of the European Union, the European Parliament may vote on
a motion of censure of the Commission. If such a motion is carried,
the members of the Commission shall resign as a body and the High
Representative of the Union for Foreign Affairs and Security Policy
shall resign from the duties that he carries out in the Commission.