If it's a big increase, you still advise them you will be terminating the current agreement, but will allow them 60 - 90 days to relocate if they choose not to pay the increased rent, pro-rated to last day of occupancy (based on when keys and possession are returned).

Immediate possession rights under older system (still applicable to over the counter sales) and immediate possession with the right strategy still possible with newer system. 

Do you possess the experience and resources necessary to successfully flip the property and generate a profit?

You're probably better off going with a 30-Day Notice for recovery of possession. 

(you'll need time to assign, market or prepare the house for tenant) Ask for immediate possession, make this a contract contingency,(unless it is occupied, than agreed to right to preview by appointment.) , Buyers need to have access to the house to show potential assignee, contractors and to market or prepare the house for tenant) Build in a automatic extension (you will always need more time) DON'T wait until you run out of contract time to ask for an extension to settlement, always include that extension in your initial offer!

I did include a clause in the purchase agreement that I be allowed to market and show the house to potential renters before taking formal possession.

They also asked for a rental agreement with tenants without even having the property in my possession.

Best of all is to (assume you possess an undergraduate degree) obtain a specialized masters degree in real estate.  

To attain a passive income of around $5,000 per month, one would need to possess a portfolio of at least 25-30 properties.

The danger is the failure to respect the power of adverse markets and the disadvantage newer sponsors possess in navigating them when they occur.When and if markets move, some will survive and some will fail.