Some areas have weight limits or large load restrictions.

Some advice (as a foreign) that you may already be doing: 1) build your credit score (use and pay credit cards and other bills and get your info - SSN or ITIN - linked to it). 2) start/improve relationships with banks, property managers, realtors, etc, this will help a lot. 3) start studying your local market (I would say, Burlington, MA as you mention you will work there), that way when you decide to invest you will be familiar with prices, location, etc and will be able to make a decision faster. 

I recommend putting a weight restriction in the lease as well as a list a of dog breeds that are considered acceptable.

Makes the 1 hour Elliptical go much faster. 3)Take action.

I think they're trying to get it right because demand is growing faster than supply, ie they need more hosts. 

I read an article about how buyers love smart thermostats, doorbells, etc...I’m wondering if adding some of those will make the property easier/faster to rent.

I would use the cashflow from the properties to help you pay it down faster and build a big reserve.

The general goal with the refinance to recover your rehab funds, which could allow you to repeat faster

Considering the lack of disclosure, inspections, and other guarantees baked into a standard market sale it doesn't seem to me like buying a foreclosed property at a 4% discount makes good sound sense unless there is a way to get a competitive advantage in the space.So, in theory "yes", but ideally this space will cool off and that discount will grow to a more reasonable risk-weighted level 

After all your landscaper already has all the equipment, has more experience and can do it faster and better than you on a consistent basis.