What I'm trying to figure out:  Is there something that is a legally binding document that the corporation and I could enter into that would show that the property is a corporate asset without being on title and allow me to circumvent title challenge Ive just encountered on transfering the title to the corporation. 

Most DSCR Lenders will require the property to be rented for a refinance (or if used as an STR for example, have some STR history)  You may be able to find an option for refinancing prior to leasing, but it will make it more challenging and will likely need a "good reason" more than just speed3.

Did you run into any unexpected challenges with the layout or structural elements?

The mistake you are making with your conclusion is assuming there is a "good list".There isn't.Many people will promise you that cold calling texting and postcards/mailers is the way to do this, but I challenge you to stand on your own 2 feet and think on your own.

The challenge for a lot of wholesalers, is once they obtain the licensing, what brokerage is going to sponsor them in wholesale transactions? 

This was a labor of love and there were so many unique and challenging aspects to the flip.

Private money is great for short term, fix and flips, small multifamily, but is much more challenging for larger deals.Gino

Its really going to come down to multiple factors, including your personal situation/strategy but it appears you are definitely thinking about things in exactly the right way.I'd say since it doesn't seem to be an "urgent" need - I'd advise talking to some lenders and since the rate environment is still moving quite a bit, settle on a interest rate / points combo that is "your number" and when market rates move down to that point - have the lender contact you and get ready to go, and just wait until that occurs

What are your biggest challenges as a new real estate investor?

Challenges?