Eliminate debt, establish a budget, and save.

A 1031 exchange doesn’t apply, but funding through a self-directed IRA can defer taxes, though profits from debt financing may trigger UBIT.To reduce taxes, consider forming an LLC for better expense deductions, offsetting gains with investment losses, or holding the property for 12+ months to qualify for lower long-term capital gains rates.This post does not create a CPA-Client relationship.

Selling it for $500K and combining that with your $100K could give you more options, like buying a single-family rental or a lake property that generates better cash flow.

If I buy out the first lender, can I foreclose with the total amount due for both loans combined, or will it remain as two separate loans, with only one being foreclosable?

From experience, I’d recommend getting pre-approved, improving your debt-to-income ratio if needed, and researching local assistance programs.

. - The money partner doesn’t need to worry about the financing or keeping the debt in their name which may reduce risk for the money partner.Long-term tenant to reduce turnover.

It's the concept of buying the debt attached to the mortgage rather than buying the house. 

I'm not motivated, but the homes needed work I didn't want to do or I did if for strategic tax or debt shell game reasons.

The combination of all the above puts me shoulders above majority of the investors.

Most lenders require proof of someone else paying the note for around 9-12 months so that the debt isn't counted in their DTI calculation.