Should I pass on this due to proximity to his work place?

No harm in developing the list 30 days in advance.

He said an unhappy seller that finds out a property was immediately resold for profit could come back to harm the agency.

Having a corporation does not shield you from actions that you PERSONALLY do or do not do that harms another.

I'm not a lawyer, so have no idea, but I was taught that if you gave permission, then you could revoke it at a later date and be within your legal rights to do so without harming yourself.

Keep in mind what's good for the goose is good for the gander and one sided obligations, as you are suggesting, won't hold water.Having such an agreement may serve as eye wash to another party and if thought to be valid, they may not seek any action against you, but if they are ever advised and an issue surfaces than such an agreement could be doing more harm than it was worth.IMO, Good luck

I don't think any magistrate or court will make a landlord keep a relationship that presents harm to that person.

You can decide later to either become a better landlord in the future or do something else - no harm, no foul in either decision.

If as my rental portfolio grows, would it be a good idea to funnel more money into my workplace 401K and Roth IRA account?

Chances are I have bigger cajones than they do.At my previous company they established a "woman's legion" to meet monthly and promote woman specific issues in the workplace, and TBH it pissed me off.