A contractor should be able to put together a box in about 15 minutes each...I would say a days worth of labor ($400) needs to be factored into the cost for a RTA kitchen if you really want to compare apples-to-apples to a pre-assembled cabinet.

This is because of less vacancy/turnover, rents increased much faster, less tenant damage, less maintenance and repair costs, and most important of all MUCH higher appreciation due to being in more desirable areas that actually improved instead of staying stagnant like many S8 areas. 

I may even sweeten the pot and offer to pay them a few thousand to help them with moving costs.

There are two types of cost in development:a.

I'm very very handy, jack of all trades if you will, so I can renovate properties without breaking the bank in labor costs.

You'll just have to compete with well connected, very effective investors here as they move fast and usually are scooping up properties quickly. 

I will likely be financing this, which is why I need to make sure it covers the carrying costs plus some. 

The cost of entry is low, and cash flow is high.You can find distressed off-market duplexes under 120k and SFH under 80k in B to C-class areas.

Any time you are next to a commercial business it can have an effect on residential properties.

Holding costs are alot on hard money loans.