I am thinking if there is any online property management that does showings and responds to any maintainence requests?

If you put it out there asking for a 3-5 year lease with a small business or startup in your mind, but H&R Block or Supercuts comes along asking for a 10 year NNN (& it's corporate) and agrees to the rent amount you requested, there's no reason not to entertain that, you got better than what you were expecting (there's a reason NNN properties, or ones with a few NNN tenants sprinkled in that are national chains, often sell for lower cap rates), it's not like taxes or hair cuts are going obsolete any time soon. 

Those folks simply can't be relied upon to relay inquiries, showing requests, etc or to put your best foot forward.  

I sent you a request to connect!

You have to now include the extra time spent communicating issues, invoices, etc..with the property owner.Whether you do it or not is not a right or wrong matter, but you need to understand why you are doing it and if the extra cash will be worth your time.We have always turned down the requests to manage other people's properties, because I feel like the amount of money I would receive from managing someone else property would not be worth the time to me.  

We always request prospective residents provide copies of the bank statements where their paychecks are deposited.

You may want to request the construction drawings / plans for the utilities that were installed to help better understand their impact to your property. 

Unfortunately, I don’t think everyone is as detailed and going so far as to request a photo of the water heater serial number so they can check the units age, and have unrealistic assumptions about their coming costs.

Do it anonymously and don't tell them the name of the property, just ask general questions and you will quickly get a feel for how they regard P My family gets constantly denied by the city for any request we ask for.

They are requesting an addendum to their current lease because their relationship has changed.