Can we impeach Trump and/or Hillary?

Why? Clown-boy wasn't impeached. God knows he should have been.

Nope. Unless your a member of the house of Representatives or the senate. You might have a chance. But the average voter does not take part.

If you mean official impeachment as in a legal process, no you can't unless they are in office. If you mean impeach in the sense of the general language (to call into question their integrity) I think that's already happening.

they have to become president to be impeached,

you can only impeach someone in "office" after they commit a crime

If, as president, they commit an impeachable offense, sure. Give 'em a minute.

They have to do something first.