Are you responsible for any common area utilities?  

This is not meant to be biased, but you will find it surprisingly hard to discuss fine project details and give important direction over cell phone with someone whose English is not good.

Will they be concerned that I have their phone number and address?

I would rather pay a professional than answer phone calls about the other tenant not taking care of their portion and dealing with that.

This will create a Tenancy in Common that gives each of you a 50% ownership in the property. 

There are similar air-to-water setups that can be used to incorporate a heat-pump into an existing hydronic heating system.When deploying mini-splits, electric baseboard (EBB) tends to be the most common ancillary heat found here - in many cases that is because the heat-pump is being installed to reduce the operational demand on the EBB - however we have deployed mini-splits in conjunction with a gas-fired central heating system.

Also, make sure you get everything in writing - no phone calls so you have documentation if you do have to proceed with litigation.  

Again, that would take finding the perfect deal which you'll likely need to do some marketing to find.A more common scenario is you might be able to partner with someone who has the down payment (and/or maybe the ability to get the loan) and you have the time and expertise to track down, negotiate, manage the deal.

I remember chatting with @Henri Meli about local deals and then he pulled up an alert on his phone on a Durham duplex(probably the same alert most of us received that day). 

There is a phone number for the assumption department, but no one ever answers the phone or responds to voicemails.