Take a pill and relax. 

However, a tenant recently informed me he has a prescription for medical marijuana.I haven't been able to determine what each of our rights are (landlord & tenant) concerning this issue.

In regards to medical marijuana - in MN I believe the only medical marijuana is used via a nebulizer or a pill, it isn't smoked conventionally. 

The girl was fine, but the two little boys acted like they were on hyper sugar caffeine pills.

It's easy to get a prescription, just like it's easy to get a prescription for Prozac or Ambien.

Blind trust I suppose is a good sleeping pill the problem is in the end you have more damage to attempt to get out of your tenants than if you bill as you go along.

For instance, if I ever want to sell the home, I want to be able to note that there is not an implied easement or a prescriptive easement etc.

It's too dangerous otherwise.Mom knows and can have health care professional writing those prescriptions call you and give you definitive answer on medication.

An emotional support animal is not required to have any training or certification.As a landlord, you have the right to request documentation regarding the prescription of the animal but you cannot demand medical records or access to the medical personnel prescribing the animal. 

Psst, take the blue pill.