Any concerns with the tenants disagreeing, funding their own handyman saying everything is fine, and the it becomes a pissing contest?

I have a SFR with a septic and make sure there is language in the lease/rental agreement that scares the %$#@%#$ out of the tenant concerning their abuse of the septic and I make sure they understand it and initial next to this language.  

But by the time they were finished, we were under contract for $140K.Purchase - $75KConstruction - $22,368Carrying/Closing - $5,052All in - $102,420Sales Price - $140KI was a little concerned with the sales price being so much higher than we started out expecting, but I didn’t need to worry, it appraised at $142K.

Maybe none of this matters and you're most concerned about cash flow on paper because it will be the property manager's problem.

In Ontario they take half a months rent for commission I believe (could be wrong about this).In terms of moving the tenants in and out for an out of province property I'd consider installing a lock with a passcode you can change digitally, that way it's as if you have a permanent lock box on at all times & you can ensure security by changing the code from time to time. 

I would be more concerned about the type of tenant than about the numbers. 

However, now that we have an accepted offer, we are concerned about a few things: Before we put in an offer in on the house, we told the seller's agent to let the tenants know that we would be raising the rent from $1250 to 1350, which is market value for the area.

Beyond the easement concern, that's something I will have to figure out when I see it in person - the area where the two property lines meet and how that may appear to a future buyer.

If you feel it is a legit concerns I would consult with local police or other security expert to see what where the property is most vulnerable the best use of of your money is to address it.

Increased water usage is the least of your concerns.