Do I need to register my startup's slogan to protect it from my competitors using it?

You don't have to register, but yes, you can, in order to give it trademark protection.

Need an advice

An at will employee may be fired for any reason, even without being given two weeks notice. You mention discrimination, but don't give details....

I filed a lawsuit, its almost over the trial date is coming, then the defendant files a separate lawsuit + Notice Related Cases.

Yes, you can file an opposition/objection to the Notice of Related Cases.

If you have an order to show cause hearing coming ioupyes, you can file a declaration to hopefully discharge the Osc.

Is it possible to change lawyers a month before court date?

Yes, you can change lawyers at any time.

What happens if you sue someone with no money?

If you lose, you will get a judgment against you, that is good for 10 years, and can be renewed indefinitely. Interest accrues at 10% per year....

Law Suit Against HOA

If the amount you are suing for is $10,000 or less, you can file in small claims court.

No, you cannot serve via fax absent an agreement. You need to serve by mail.

My employment agreement is at will and states either party can terminate without any reasons or notice. Can I file a law suit?

If you were fired for reporting/complaining about activity that was illegal, yes, you could have a viable retaliation and wrongful termination claim.

Both have 3 years statutes of limitations.