I have a lawyer can he show up in court n speak for me without me being in court with him?

depends on the case. ask him

Yes a lawyer can in many situations, however depending on what is being done in court the judge may still want you present. Your lawyer will be able to advise you on your personal situation.

At some hearings, yes. At other hearings, no. At trial, no - you have to be at your own trial.

There are some sorts of court appearances in which the client may waive his appearance. And there are some where the client's appearance is mandatory.

If you have committed a crime the you have to be there, if it is a claim you have raised against someone then no you don't have to be there

In most cases, yes, consult your attorney.

Not as far as I'm aware of. You should be there.
Peace.