Hi Stefan, Finding a passive money partner for your real estate investments, particularly for fix-and-flip projects, can be a fantastic way to leverage additional capital while spreading the risk.

PM me address and any additional info and I would be more than happy to run some numbers for you. 

If not why would you let them buy a completely flipped property at a discount. 

Wedding people, bike rider groups, extended families in addition to one big family.

They are inside (above) backyard at 25% inside property line back fence.Personally I would not buy it to stay permanently as primary (don't mind to stay year or two as tenant) but it is for investment and I can get some discount for this reason.

I have yet to see a hands off ADU addition obtain a valuation to cost ratio anywhere close to approaching what you site ($210k cost to add $350k of value).  

However, in addition to this fee, there may be other costs such as title insurance, property transfer taxes and others.

This type of financing will typically look very different and more like a traditional commercial real estate loan.That means a DSCR calculated based on a full NOI and expense load (so inclusive of vacancy loss estimates, credit loss estimates, repairs and maintenance, utilities, management fees and more – in addition to the property taxes and insurance expense that are the only expenses factored in on traditional residential style DSCR loan financing).Additionally, the DSCR minimums are generally going to be higher (typically up to 1.25x), the loan to value ratios lower (higher down payments) and underwrite more sophisticated (which makes sense considering the size and scope of the property).Many multifamily investors for properties of this size (such as more than 11 units) can syndicate capital and have more sophisticated financial and entity structures – its definitely a different world once you get up here in unit count.In Conclusion – when you are looking to invest in multifamily real estate and finance your investment – make sure you have the unit count in mind before you start shopping – the unit range can have a huge effect on your options.

Before I continue developing, would this be a useful addition to an agent's toolbox?

This, with the addition of a second commission AND the potential of a passive downline, is what made me get excited about this product to begin with.