I only ask because that is, in my opinion, the most challenging part.  

Quote from @Jeffrey Hill: There are a couple of challenges with financing the difference. 1) The current servicer has to approve it. 2) Finding a lender to do a 2nd mortgage at 100% CLTV is almost impossible.

Challenges?

From reading other posts this year has been particularly challenging. 

Unrealistic construction budgets are an issue new investors often face.

Removing a lien is challenging because you need the person who placed the lien to sign off to remove it.

Challenges?

This concept aims at addressing the challenges of what to do with defunct suburban malls and maybe even empty big-box retail store spaces that are in desirable and affordable neighborhoods.

See the chart from Fair Isaac Company (FICO) below: FICO Score Pct of Population Default Probability 800 or more 13.00% 1.00% 750-799 27.00% 1.00% 700-749 18.00% 4.40% 650-699 15.00% 8.90% 600-649 12.00% 15.80% 550-599 8.00% 22.50% 500-549 5.00% 28.40% Less than 499 2.00% 41.00% Source: Fair Isaac CompanyAccording to this chart, investors should use corresponding vacancy+tenant-nonperformance factors of approximately 5% for Class A rentals, 10% for Class B and 20% for Class C.To address Class C payment challenges, many industry "experts" are now selling programs to newbie investors about how Section 8 tenants are the cure.

Knowing the rent will likely show up each month—even if the tenant has challenges—removes a lot of the uncertainty that can come with rentals.The people listing this apartment as a “Section 8 property” are likely trying to target buyers who value that stability.