The problem (as you have cited) is trying to understand what you need (you don't know what you don't know), where to get it, qualifying its source(s), and the validity and usefulness of all that.Pardon me if I've gone into this too much, but I meet many people with the same concerns that you are voicing and this is offered, as much as possible in direct response to your post.Please feel free to contact me if you have any comments or questions. 

Then tell us the nature of your remaining questions and concerns as to each remaining aspect, so people can have intelligent, focused, SHORT, conversations with you on each issue you present. 

It could certainly be a concern - but depends on a lot of factors - are you looking multi or SFR? 

The concern with places like Irvington will be once you move out and no longer owner occupy how do you raise rents legally.   

I could care less what happens to the prior homeowner or if they go after him, as far as I am concerned.  

My main concern with the Japanese market is that I really know nothing, and I find it a bit hard to find information about it, but I guess I also know "nothing" about property markets anywhere other than maybe Hong Kong. 800 square feet is not tiny by Hong Kong standards, you are absolutely correct, but just as you mentioned we have a live-in helper and are hoping to start having kids about 1.5 years later.

Knowing how fast or slow things are turning would not cause me to change how I manage my business.I'm more concerned about current market rents  All else equal, I know that by lowering my rents $50 or $100, I can lease up my units almost instantly. 

When 99% of transactions have commissions above 2%, it's essentially a fixed rate, not a truly negotiable one.I respectfully disagree with the concern about "buyers that don't have money to pay a commission to buyer agents."

If My father and I use the heloc to fund the repairs; I'm concerned to have payments on a heloc as well as giving up all the cash flow for a period of time.

If you want to keep your options open to access more deals, it’s worth having an honest conversation with the agent about your concerns.