Some prospective tenants first inquire and later reveal that they are section 8 , can we just ignore in this kind of situation?

This progress reveals owners and chains of title. 

The horror stories you hear around the grapevine almost universally have a "catch" they are not revealing (eg, the investor either said or did something improper in the transaction that caught the eye of the state regulators). 

Renovations often reveal hidden issues.

Once that happens, the tools of cash, finance or seller finance or deal structuring start to reveal themselves for me.   

If this is a small job under $2500 labor- flooring. painting, new cabinets and you called four contractors and are revealing you are shopping five guys then a contractor might not have the time or desire to teach you.If this is a whole house rehab or stick built then you need everything itemized, plans, specs, and costs all itemized.

I guess I'll reveal my ignorance with this post, but what exactly is a "hub"?

So far all have said they fear the hornet's nest it could stir calling out the BS operators, lies, distortions, pulling back the curtain and revealing the truths to the whole gambit of those selling "Wonka's Golden Tickets".   

There are a lot of market experts here, so I'd just reveal that if I were you because you can get some real data on what to expect. 

Do not 'just get it snaked'...that will not reveal the condition of the interior of the pipe.