Should I use a co-host just to get off the ground on a good foot and rack up some solid 5 star ratings, then transition to self sufficient down the road?   

Choose the Right LocationProximity to Campus: Prioritize properties within walking or biking distance to minimize transportation costs.Safety and Security: Research neighborhood crime rates and local security measures.Access to Amenities: Look for nearby grocery stores, healthcare facilities, and entertainment options.3.

it makes for a very juicy internal rate of return.

You have to put more money down and pay a higher interest rate and is limited to only 2% IPC.

Curious, what sort of cap rates do you see in Japan? 

As-is cap rate of 7.5% in my market (kc) would be pretty awesome to buy. 

When doing a full due diligence on these companies, I found out that their trustpilot rating was 1 star and read several lawsuits filed against them, by multiple homeowners.

Is it a viable option and what could I do to increase my success rate when taking this opportunity?

So this is creating more competition and more agreesive rent rates and/or concessions like 1 month free to get those vacancies filled.

I agree with the others here that say you need to have some skin in the game, if you are going to live there yourself, get an FHA loan rather than owner financing, you can get a 3.5% down loan, personally I do not love these as they require  PMI which is an additional expense, and you also need  bring additional funds for closing at least for taxes, title, attorney and transfer fees . borrowing from anyone else for the down payment, to include a personal loan from the bank is not a good idea, those again will be higher int. rate.