Non-Recourse Loans

If a private non-recourse lender to my IRA or Solo 401K wants more collateral than the property I’m buying, can I pledge as collateral an additional property already owned by the same retirement plan by doing a separate additional deed of trust? (I’ve heard you say that non-recourse loans usually must prohibit the lender from being able to take other plan assets.)

Alternatively, can my IRA or Solo 401K pay a guarantee fee (up-front or over time) to a financial friend who is not a disqualified person to be a guarantor on the loan (that person being personally responsible in the unlikely event of default)?