Rates are currently averaging around 7% or higher most of the time right now (insert disclosures about creditworthiness, etc. here).

I went from the low 500's to almost 700 in a little over a year and i'm at the point in my life where i feel credit worthy now.  

I've only in recent months decided to pursue real estate investing and I want to be maximally positioned as a credit-worthy borrower.

Even if there's a small chance of getting caught, I'm not going to risk 18 months in the clink plus big fines and having my loan called plus ruining my creditworthiness just for a lower rate personally, but I'm not a gambling man. 

I don’t want to mess up my lender credit worthiness but if the student loans are paid ahead and no payments are required, it would be nice to build a larger cash reserve.  

I agree SFH are more risky for investors based on your two points, but we are in a prolonged SFH shortage, and homes are the gold standard of rentals so only the best creditworthy people should be renting them. 

You’re probably looking at a half a point or more depending on your credit score/credit worthiness

Assuming seven years remaining and you want some margin of safety against rising rates and the fact that you don't know a lot about the credit worthiness of the borrowers (though you should see their files as part of DD) I'd have a required return of at least 14% so that makes the notes worth about $73.5K Another option is not buying the notes at all since you don't know if they are SAFE act compliant and you can avoid the hassle/risk.Total price: $330k-$450k, but you'll put finer point on that once you get into DD.

I do credit checks, but the best indicator if the tenant is credit worthy is how he handles the deposit, If he says no problem, no hesitation, he's OK".  

If their creditworthiness is in question, ask for 3 years of tax returns and financials on the tenant.Best of luck!