Managing 25 properties worldwide, I’ve scaled operations to generate $1M+ annually, which led to acquiring a hotel in Costa Rica.

When pulling the credit report one of the individuals has a high debt to equity ratio (50 %) My fear is what if this High DTI and credit usuage could result in one of the parties defaulting on future rent.

If a cash out refinance, many lenders will allow the cash out to satisfy the reserves requirement.DSCR lenders generally let you vest either individually or as an LLC.

They snuck under the rules by claiming that private individuals had the right to offer other private individuals the service.So again, how do these cities get away with regulating people's abilities to rent their homes on a short term basis? 

If you want to be mentored your best bet is to go work for a company - most CRE is not a single individual and CRE is fast moving and things happen fast and you can't structure a "follow me to learn" without working for someone 

.- The variety of financing products available as individual tenant in common loans remains limited, and the terms are generally less favorable than either apartment building loans or condominium loans.

Personally knowing the founder of BP, Josh Dorkin and the current CEO, Scott Trench, I can tell you that their intent in starting and growing the bigger pockets community is to encourage investors of all experience levels to share their experience and network with like minded individuals. 

Or do you know of any groups or individuals working in this space?

Or do you want to generate off market deals.

You can maximize your cash this way with the lowest rate possible on the debt and be able to reinvest all the while still generating cash flow.