My plan is to will my money to a charity in such a way that the principal will survive and the charity will receive a large portion of the annual interest on it to use as funding.

I really think the " QUESTION" is do you raise rents... if you do you keep up with inflation, if you don't your a charity,, Does the gas station at the corner care if you drive a beater or a new car??

Landlords planned for a rainy day, but they didn't plan for the federal government to come in and tell them that their business is now a charity whether they like it or not.

He is not a charity! 

You're in a business world, not a charity 

@John ReelIf this potential mentor is genuinely doing well at their business, their goal for this meeting is to find how you can contribute to that business.Unless this mentorship is a charity (<1% chance) you will have to add value to this relationship.Ask questions such as.What are we in the business of doing?

- How can I maximize the good (Do I give money to a charity?

First you are correct this is a business not a charity or non profit or community service, save community and charity work for the part of you life that you have dedicated to those causes, which by the way is a must if you want to be a complete self actualize person. 

Never ever ever mix friends and family with business unless they are in a dire emergency and you are ok being a charity for them.

Donate the property with the now lower lien amount to a charity and get the tax deduction (50% of the value of the property?)