That's all the debt I have.

@Julio Cruz that makes sense, but if the house is worth 700, they sell it, subtract broker fees and pay off the outstanding debt, like you said, they're left with 450K.

I focus on total return: value add and market appreciation, third-party debt reduction and cash. 

@Bob CarrollYes, leveraged income to an IRA generates UDFI (Unrelated Debt-Financed Income) that will produce a need to file form 990-T and pay UBIT (Unrelated Business Income Tax).Look for a CPA who specializes in tax-exempt and non-profit entities. 

My intent it to use it to pay off some short term loans debts to improve my DTI and credit score, then refinance my house and put it back into the ROTH in roughly 6 months from the 'cash out' of the refinance while rates are still great.

If you don't have enough Solo 401k funds to purchase the property as an all-cash deal, you can combine your Solo 401k funds with non-recourse debt to purchase the investment property.

Lastly, I'm pretty familiar with real estate financing (debt structuring) and tenant policy.I would really appreciate any of your strategy, opinions, ideas, advice, or feedback.

Do you think I could get a loan that way or would the fannie/freddie underwriting guidelines dig into all my rental debt servicing etc and not be able to lend?

Thanks @Cody Barna -  I watched a lot of family & friends fall into debt because of them. 

A little less forgiving during the holidays or middle of winter.