My mother was forced by the conductor of the Amtrak to explain what her medical condition was in front of a room full of people

Other than writing a letter, not much. I doubt she'll want to pay potentially thousands to file a suit and I don't think her situation will appeal...

Where do I start first?

You can file a charge if sex-based discrimination with the EEOC or MCHR.

What is the difference between to I testify for myself and I plead pro se ?

Hire a lawyer. The fact that you can affirm to testify truthfully rather than swear is but a small clue that you are in no way equipped to defend...

What if my landlord is trying to wrongfully evict me, has been harassing me over the last year and causing me emotional distress

Comply with your lease obligations. If you get sued, show up at court. Hire an attorney if you can if you get sued.

How can I prove for the courts, that I made store purchases several months ago, when I failed to keep my store receipts?

You provide oral testimony and hope the judge believes you. If you paid by check bring proof. If you withdrew cash to make the purchase, bring...

I need help wording a letter

You should hire a local probate attorney.

Can I sue a storage facility if they wrongfully removed my items?

If you file a lawsuit, then the answer is yes. Depending on the value of the items, small claims court might be a good option.

I filed a small claims case 2 court dates. One says dismissal 3 months after the first date.

A dismissal hearing is a date the court sets such that if you don't serve your ex by such date and don't get a new summons issued the case gets...

Can i actually be sued?

Unless the Texas law firm has Missouri barred attorneys you might have an FDCPA claim based on a threat to take action that the debt collector...

You should show up if you were served. Request a continuance to get an attorney or to take discovery. Good luck.