If you can purchase this home with private money or seller financing and get a $110k loan, then you could do a rate/term refi right after so do a 90 or 120 day note to secure the property and get it in your name, then refi into long term debt using the full appraised value. 

However, they can deduct the interest they pay to you as part of the seller-financed agreement—if the loan is secured by the property and you provide them with a Form 1098 (Mortgage Interest Statement) for their records.

But what is really important is that you understand the terms of the loan, including the length of time and when you can expect to get the money back, how it is secured, and the process of getting it back if things don't go as planned with the investment.

Do you have any suggestions on how we can secure long-term financing under these circumstances?

I completely agree with @Ashish Acharya's points about the cost-effectiveness of a HELOC and the potential credit implications if it’s secured by your primary residence.

I was hoping for some idea to secure the Promissory Note but it seems that's not available.Thanks for your response. 

The online eFile providers can do it for you, sometimes for free.Warning: Email is NOT secure, and you will expose your contractors to unnecessary risk of identity theft.

Hello fellow investor,Thank you for your interest in learning more about our company and how we secure funding for our clients.

You have the ability to grant permissions based on the user's security level, which you determine.

This could help secure a higher LTV while you build STR rental history.