Your choice, but before you do it you have a decision to make. 

But before you go download any old real estate app, it's good to know that there are a few different types to consider: Some have a larger volume of house listings, while others are more geared toward commercial real estate and even auction properties.

The largest pool (no idea on %) have never done a larger multifamily deal, maybe never a deal at all. 

If it's a larger organization, feel free to inquire about their different staff qualifications.2.

The increased/inflated supply of money leads to larger/higher prices - sort of like how increased air in a balloon leads to a larger balloons - as people can "afford" to borrow and therefore "afford" to pay more.On the other hand, there's not much money at all available to borrow to rent! 

While Watertown probably would not be our first choice otherwise as an investment location, he will be there with the Army for 2 more years and has to live somewhere and house hacking always seemed like a great option.

Given the cost of tile and time, it certainly isn't worth cheaping out on mortar, but modified is not always a better choice.  

The easy solution is to refi the first HELOC into a larger one, but the issue is that the only banks I am finding to do HELOCs on rental properties will only do 60% LTV.

Generally an S Corp is not the best choice for holding rental real estate. 

There seems to be an endless supply of newer better as far as residential renters property choices.