You have not recited any damages. If no damages, no lawsuit or recovery.

You may file petition to probate estae. I need much more case specific information to further advise. Link provides...

Not enough information provided to opine on whether your rights were violated. Consult elder rights counsel in Oklahoma.

If deceased beneficiary's right to distribution have vested, they should be distributed to his/her heirs or beneficiaries.

Best option may be to petition to be appointed conservator with specific authority to sell real property.

Sounds suspicious. I need more case specific information to further advise.

Yes. Mother may serve "cheap xerox printed copies of her paperwork she filed" as long as readable..

Yes. Biological father may petition to terminate guardianship. You may hire counsel to oppose. Link explains: https://www.courts.ca.gov/1213.htm

No. California trust does not require Form DE-60 for validity.

Any interested party may challenge validity of trust. much more case specific information need to comment on strength of your case.