I primarily invest in BRRRR exclusively and just completed a three unit on Granada.

I can own a property, have a mortgage on the property and still sign a lease to rent the place to a tenant.The transactions are not mutually exclusive.

I require holding monies to lock up a unit exclusively. 

I'm a real estate agent that works exclusively with investors.

Generally yes if you meet several requirements such as, your rental activities qualify as a business, you use your home office exclusively for your rental business, you use your home office on a regular basis, plus a few other requirements.

Here are some potential strategies:Primary Residence Exclusion (Section 121): If your dad has owned and lived in the home as his primary residence for at least two of the last five years, he may qualify for the Primary Residence Exclusion.

The exclusion only allows you to claim it once every 2 years. 

Business Use of Home:If you are using a portion of your home regularly and exclusively for business purposes (in this case, creating content for your YouTube channel), you may be eligible for a deduction related to that business use.

Think 3+ flips per year or providing property management to 5+ non-related property owners.You can setup a SDIRA and invest passively and at arm's length in things like rentals or private lending exclusively for the benefit of the IRA.There is no intersection or middle ground between those two options. 

Are you a PM exclusively?