If you're house hacking and one spouse does qualify as a real estate professional (license, active hours, etc) does the the fact that a portion of the property is your primary residence affect the ability to write off all loses on the other spouse's income? 

As I use the BRRR strategy, an important factor for me is the ability to refinance quickly.

This will affect your ability to obtain conventional financing for 3-5 years. 

Everything considered it is probably a good business model for those investors who have the ability to deal with people with "more limited" resources.

Pay your parents back with your rent savings, and then build up another war chest to go buy another property.If you don’t have the ability to borrow your down payment, then you’ll need to hustle and find a way to save $20K or so.

BUT, in this below article it states that a bill was passed to ban discrimination in Maryland.

Search for the proper deal where you are buying at an actual deal where you are buying with equity or will have the ability make improvements to add equity.  

However, if they don't have enough collected funds to cover new roofs or decks, they will just do a special assessment and you might get a bill for $3000 for new roof.

Realize that a credit history is a reflection of one's ability to repay debts in the past, and most lenders will use this as a forecast of the investor's ability to repay in the future.

With your experience and ability to open a brokerage it sounds like you've got some great experiences to share and will be able to move forward!