Once I received the purchase agreement/settlement statement, I noted the following:Pro-rata share of debt: $457K, Total Purchase Price of $1.08MM (the fund due from the investor is still indicated as $600K).Since the debt service is paid by the Trust, I am a little confused as to what this total means... 

Here, several investors (including SDIRA’s) can lend on one first position loan at the same time by sharing their pro-rata (fractional) interest.

It seems that as long as I am not personally using the investment properties and that whatever principal and pro rata share of profits from the deals went into the SDIRA trust that it would be OK.  

However the likely scenario is that there will be x amount of money left for all unsecured claims which will be divided up by each creditor's pro rata share and distributed likewise.I am also speaking in terms of a Chapter 7 bankruptcy.

Any assets converted to a Roth IRA are treated as consisting of pro rata portions of basis (if any) and pretax assets.Conversions to Roth IRAs can be done either directly or indirectly and are reported on Forms 1099-R and 5498. the Roth IRA owner must report conversions on Form 8606, Nondeductible IRAs.An IRA distribution that is directly converted to a Roth IRA is reported on Form 1099-R with distribution code 2, Early distribution, exception applies (for IRA owners under age 59½), or code 7 in Box 7.

You will certainly want to coordinate with your tax advisor to ensure proper reporting and consider the pro-rata rules" I am NOT SURE, what does pro-rata rules means?

The idea behind Chapter 13 is simple:  Debtor's income minus reasonable allowed expenses equals payment amount available pro-rata to creditors. 

For purposes of this subparagraph, in the case of an S corporation, an allocable share shall be the share holder’s pro rata share of an item.

I have a commercial property owned by one LLC & rented out space to my other 'management' LLC at a nominal rate.The IRS auditor didn't agree..but they did allow me to take a full office deduction with a pro rata treatment of expenses etc.The latter proved to be a much better (creative) deduction.

In most transactions you would pay the pro rata share of taxes based on the date the deed transferred to you as the owner.