He insisted that there be a clear decision maker when there is an impasse and made me a 51% partner.Also all of my partnership agreements have a buyout clause.  

While credit checks aren't as important though I would still insist on a criminal background check, wouldn't want to introduce people to the neighborhood who are likely to be into criminal activity, especially if they were registered offenders. 

A separate lender insisted on a DEL LLC.Good luck!

That type of commingling is not permitted, and you could end up being responsible for the complaining tenant's electric bill.Make sure to have the work done by a licensed, insured electrician and make sure they pull permits and have inspections as needed--your local utility provider will probably insist on that anyway.

Collect rents if some tenants insist on paying cash?

I insist upon a double security deposit to mitigate any sporadic cash flow (never allowed to be used as rent, but covers me a bit more if there is a problem and we need to part ways).

The whole trick is they compare future dollars (the saved interest) to present dollars (what you pay now) it's not the same no matter how much they insist it is.

We also insist on  renter's insurance.  

Here's another article you may find useful if you insist on using excel and are interested in the IRR (Internal Rate of Return). http://www.privatemoneylendingguide.com/investors/articles/hard-money-loans-irr-internal-rate-of-return

If he insists on monthly payments I would try to negotiate them down to as little as possible.