Like Jay said, there can be more flexibility in repayment options. 

Any laws against repaying the loan in stocks instead of actual cash?

.: Quote from @Jennifer Turner: Has anyone ever sold a property with seller financing then later extended the repayment period or modified the terms of the loan with the buyers?

Here are a couple of ways you could structure the deal:Lease Option with Seller Financing: You could lease the property with an option to buy later, allowing you to rehab it while giving the sellers time to find a 1031 replacement property.Seller Financing with Deferred Payment: Structure the seller financing with no immediate payments, allowing you to refinance once the property is appraised, and the sellers can complete the 1031 exchange when ready.Escrow Holdback: Transfer the deed into an escrow account, giving you control without immediate transfer, so the sellers can take their time with the 1031.Third-Party Facilitation: Use a qualified intermediary to hold funds and facilitate the 1031 exchange while you refinance.These options allow flexibility for both you and the sellers.

Several of the contractors offer helical piers but don’t seem to think they’d be a more cost effective option - we can directly ask about this again.  

Another option could be a home equity line of credit (HELOC) if you have enough equity in your primary or second home.

If the rent stabilizes, I can then consider refinancing these properties using DSCR or other valid options (please educate me, and let me know what other options you think are valid).

I also want to combine it to one $150k  30 year fixed loan instead of having two separate  $100k and $50k loans what options do I have can anyone help.I don't want to use my own money.

The more cash on hand the more options.

Just make sure the town is ok with the land being zoned for multi-units, and look into construction costs, financing options, and permits ahead of time.