I now inform all prospective buyers ahead of time that I will send my painter in as a 1 time courtesy once they complete their move-in to touch up hallways.

When they apply is when you should confirm their identity.  

Learn what each one of these are, and see which makes the most sense to apply to your specific financial plan. $150 cash flow on any rental especially a triplex is dangerzone imo. 1 month of vacancy of 1 unit could destroy a years worth of financial gains.  

Prospective tenant views apartment and decides if they want to apply.3.

A 1031 exchange doesn’t apply, but funding through a self-directed IRA can defer taxes, though profits from debt financing may trigger UBIT.To reduce taxes, consider forming an LLC for better expense deductions, offsetting gains with investment losses, or holding the property for 12+ months to qualify for lower long-term capital gains rates.This post does not create a CPA-Client relationship.

He's placing the money owed the painter to complete the staining in esrow since weather won't allow it to be done before closing.

Here are a few suggestions to help with the process:Use Zillow or a Similar Platform: If you already have a Zillow listing, having them apply through there is a good option.

Might be good to apply to real estate.  

I plan to prime the whole house and then have a painter come in and paint.

The same also applies when considering a lease renewal or temination.