I've heard it may work better to hire a lawyer to arrange financing, than fly back myself (target area still undecided, leaning towards OH or IN). 

There are a lot of examples online for partner arrangements for you to research.

I am really hoping we can keep the arrangement working in my next level as a landlord but it will be entirely up to you.

Now that you have your personal living arrangements covered , take the rest of your savings and keep some for emergency .  

Some need to be answered up front just to determine if you want to spend the time worrying about the opportunity. 1) I'd verify that the seller owns the properties and there aren't any unpaid liens, unmentioned other owners, legal issues, drug lords living in the premises, that kind of thing. 2) Verify as close as possible what the actual value of the properties are. 3) Find out why he wants to sell. 4) Depending on the underlying note, see if there is a Due on Sale Clause. 5) Check and see if the properties are cross collateralized 6) Have a plan in place for property management 7) Ask for the rent rolls 8) Verify taxes and monthly, yearly maintenance costs 9) Your Owner Financing arrangement needs to be written by an experienced local real estate attorney 10) Call a couple of banks and ask them if you will be able to refinance the properties in two years per the agreement.

I'm trying to find ways to partner with other investors so that they can benefit from my special arrangement.

You can give them the apt. for free for doing the general maintenance, bookkeeping, etc. or some other arrangement you are comfortable with. 

It's far safer than working on ladders, and it also has some unbelievable storage space.On the possibility of the business arrangement per the previous post, we actually had a business arrangement gone bad, of sorts. 

I know that my 2nd and 3rd properties will go more smoothly, so I can arrange repayment to my HELOC more easily.

Now even if both parties agree to the arrangement, there could be various legal and tax issues.