If you truly gave them your best offer, and they didn't bite and are 100% opposed to holding any type of paper, you need to appeal to the emotional side as opposed to the analytical.  

The idea of putting little to none of my own money down and building up passive income obviously has its appeal. 

If they would not deal with you if you disclosed exactly what your intentions are, so you omit parts to make it sound more appealing to the seller, its unethical.

Make it awesome in regards curb appeal.

Updating the exterior areas can be done for pretty cheap and increase curb appeal greatly, giving off that fresh new look which can attract tenants quicker and help justify an increase in rent. 

I could see why renting by the bedroom with lower rent might be appealing. 

.), they are worth far more from an aesthetic standpoint.

Especially these days where SS appliances are the same price, there’s no microwave and appears to be no room for one, all doors are flat panel, for a few dollars I would have liked to see them switched out for 6 panel doors, there’s no recessed lighting in the house which is essential IMO when trying to sell a remodeled house, there seems to be wood paneling in the house that was painted over, the bathroom is very bland, and perhaps one of the most important things I noticed is the paint job, there is absolutely no appeal, no color, no anything.

There are ways to appeal if they don't count a unit, like referencing mid-1950 water records, but I wouldn't bank on that as a buyer. 

I also have the option to partner (silent) in with someone who is willing to invest up to $100k for 50% of the deal which will basically just buy me the property, but i'd still have to come out of pocket for the reno.Not sure if either sound appealing and wondering if anyone has a recommendation which might be the better choice if any at all.Many thanks