In retrospect, some yellow flags found by the property manager during the tenant screening are now bright red flashing sirens, but the tenant showed decent credit, had a positive previous landlord reference, wrote a charming cover letter in his application, and applied through the referral of a reputable real estate agent.

Not sure of their reputation, any insight or tips for navigating this process at all are apricated.  

Yes, most of the reputable lenders have a min loan amount of 65k - 75k with a minimum of 40k - 50k of that amount going toward the purchase.I've been down this road before with a few investors who want to buy cheaper homes and what I can tell you is that - 1) It's not easy and 2) You WILL NOT like the rates, fees, and points.Think about it, what does a lender stand to make on an interest only loan for about 40k. 

Any advice on how to source reputable contractors in a specific area?

Try searching buy house with section 8 voucher in "your state" and see if your states web page pops up with this information.

Then, when filing your entities, you just paste your FinCEN ID number into the field on the web form.

It offers a secure and transparent process for both buyers and sellers.NoteTrader Exchange: An online marketplace where you can list your note for potential buyers.LoanMLS: A marketplace for buying and selling mortgage loans and notes.FCI Exchange: Another platform where you can list and sell your notes to investors.Note Investing Forums and CommunitiesBiggerPockets: A popular real estate investing community where you can network with potential note buyers.LinkedIn Groups: Join groups focused on note investing and real estate to connect with potential buyers.National Note Group: An online community where you can connect with other note investors.Note Brokers and BuyersNote Brokers: Engage with reputable note brokers who have access to a network of note buyers.Local Real Estate Investor Groups: Attend meetings and network with local investors who might be interested in purchasing your note.Financial InstitutionsCredit Unions and Community Banks: These institutions may be interested in purchasing performing notes.Private Equity Firms: Some firms specialize in acquiring performing mortgage notes.I hope this give some direction regarding your situation.

If you're solely looking to invest passively longer-term you're probably better off finding a reputable syndicator and investing passively. 

The lender will know who the more reputable builders are in the area. 

This is not how most reputable, experienced investors do it though.