As Jay and I have warned, WAY too many of the people grasping to this SubTo method SHOULDN'T do it.

The hilly terrain is a main reason for this and you can't really see that on a map so knowing the areas is key.We have old housing stock as well so big things like plumbing and electrical can vary cost wise if they have or haven't been updated.

You'll likely also reduce your cost of living by moving to a stabilized apartment.Depending on the cashflow and debt paydown, you can use this strategy until you've built enough equity to reinvest.On the other hand, getting into a multi-family after refinancing will also help you build substantial equity to rinse and repeat in the coming years.

If its four months from now, then explain to him he's going to be evicted, will have a record, and it will go to collections for all court costs and rent money owed, to the penny.

Is there any good rules of thumb to estimating the cost of a boiler?

If a large repair or tax/insurance hike were to happen with a multi-unit than you at least have other units cash flowing (usually) which helps stabilize such unexpected costs. 

However, this has to be the primary residence of everyone on title in order to qualify and even if that were all true, we're still only up to $1M that way.I agree with the other commenters, the parents should continue to own it and live in it as their primary, leave it to the daughter when they pass, and she inherits it at the stepped up cost basis. 

Whether the seller was open to a buyer commission or not, I wouldn't put an additional cost into any personal purchase.  

For example, should we focus on acquiring one high-quality property in a strong market, or would it make more sense to spread the investment across multiple lower-cost units in emerging areas?

I do understand all recent syndications are struggling with costs and tenants struggling to pay, so trying to be patient for now.