Talk about drinking from a fire hose! 

If the investor is putting up $500k of their own money and you're just managing it and you're going to make a $40k profit on the flip...than they will probably want more than 50% because they have a lot of capital on the line to make $20k but if you are talking about $200k than a 50/50 split would be more in line.

Talk with the lender you are interested in using and see what they require.

Also, if anything ever happens, like say a fire starts in the basement duplex and travels up the stairwell you illegally built killing everyone inside, then you are not only talking financial liability but criminal liability as well.

I've talked with a couple (Morris Invest and Norada) so far and plan on talking with a few others.

The chances of BofA talking to you are slim unless you had seller sign a POA and/or 3rd Party Auth Letter. 

Don't talk about it, be about it man! 

So use the rates you see published as a guide and then find a bank or mortgage broker to talk to about your individual situation to see what sort of rate you can qualify for. 

I see a lot of talk about  the new crash coming.  

.3You should look at the actual leases and talk to the tenants and confirm that is what they are paying.