Substitution of Trustee not Recorded (for years).

We have some interest in an unencumbered house in LA County. According to Title, the property is currently held in a Trust. One of two sons (#A) lives in the house and his mother is listed as the Trustee. But she died about four years ago. Brother #B is a real estate agent, and is apparently the Successor Trustee, with both brothers named as Beneficiaries.

Originally, both parents were the Trustees. But when Dad died, a notice of change of Trustee (to Mom only) was recorded (about five years ago), along with his death certificate.

Title deed language indicates that the Trust is Irrevocable. But obviously, we need to see the Trust docs, if they can be found. But this raises several questions. Eg.

Is it acceptable for Brother #B (the Agent) to act as both Trustee and (partial) Beneficiary, or does that automatically dissolve the Trust?

Is there a requirement to report a death (of the Trustee) and subsequent Substitution or change in Trustee status? What Regulation/Law is that? Is it in the Probate Code and/or County Assessor Rules?

We understand that Ca Proposition #58 may preclude property tax reassessment, but does the County Assessor need to be informed of the change? Or did the change effectively occur when the Trust was initially formed and recorded?

Are there any penalties for not Recording the change? Even if there is no Property Tax ReAssessment, (or Probate) are there Documentary Transfer fees, Capital Gains Taxes etc due?

My apologies for the long post, lotsa detail. Just trying to be clear.