Would the seller be interested in carrying a 6 or 12 month note for you for the remaining downpayment amount to buy some time to liquidate the condo?

You or anyone else can take title to any remaining percentage.You also need to remember that you must use all of your proceeds in the purchase.

Do 1031 rules allow me to use the proceeds from the sale of the first property to purchase the remaining 50% of the LLC that I don't already own...assuming the numbers line up?  

Rate lock: If you've already locked in your interest rate with the lender, it typically remains fixed for a certain period (often 30-60 days), regardless of market fluctuations.

And she'll do a 1031 exchange on the remaining three units.  

s, first rent of the newly created unit must be equal to the combined rent of the two previous RS units..in addition, newly created unit will still be regulated, NYS senate just passed bill S2980C..Substantial rehab is the only remaining strategy, which is not cost effective in the current market

(A) Any security deposit in excess of fifty dollars or one month's periodic rent, whichever is greater, shall bear interest on the excess at the rate of five per cent per annum if the tenant remains in possession of the premises for six months or more, and shall be computed and paid annually by the landlord to the tenant."

For buyers or their brokers with well capitalized investors, inquiring directly for verification of a property whether it has an assumable note is good practice while interest rates remain elevated. 

This provides a steady income stream with minimal risk.Appreciation Potential-The property has appreciated significantly since purchase, and you could continue to benefit from further appreciation in the future.Minimal Hassle-You're already familiar with the property, and since it's paid off, you don't have mortgage payments or associated risks.Cons:Limited Portfolio Growth-Keeping the property means your investment portfolio remains concentrated in one property.

This step ensures that your IRA remains compliant and that you don't inadvertently violate any regulations regarding personal guarantees or liabilities beyond the property itself.