Can I get fired if I join a law suit against my current employer?

If you are fired simply because you joined a lawsuit against your current employer, you may have a retaliation claim. It would be prudent and wise...

Side issue: Were you paid time and a half for overtime (hours worked over 40 in a given workweek)?

How far back can a company look in order to pay overtime owed?

Under Federal law, you can generally go back up to three years. Under state law, it varies greatly. Contact an attorney directly to go into depth.

Does a new employer ever file an order to show cause to hire someone with non compete issues

This would not be the best strategic approach.

My employer is participating in ritualistic cheating customers & mislabeling the origin of the ingredients he sells.

If you report any illegal activities that your employer is engaging in to government agencies you may have certain whistleblower claims.

Can a class action survive in an employment case if the plaintiff also has legitimate individual claims?

There are many ways to handle the issue. For example, there can be subclasses.

My restaurant transferred me due to a sexual harassment claim from an employee (a guy) the whole restaurant talked about it.

You may have a claim , possibly for retaliation, discrimination, or otherwise. You may have no case at all. Speak with an attorney to flush out the...

Was I discriminated

You may have an FMLA claim. You may have been fired for cause and thus have no claim. Speak to a lawyer regarding the details of your case.

Do i answer all the discovery questions I received from the law office that is suing?

Ask your attorney.

Being harassed by the CEO of my company, what can I do?

Nothing you mentioned sounds actionable under the law. Obviously, employers are entitled to be based overseas, to give their employees heavy work...