The end goal is to have have to have enough parking for a single vehicle per unit, to separate the water and electricity, and to convert the single family into a duplex. 

If audited, you have to prove that the payment did happen. 1099s is a separate issue which the IRS might raise in a audit but usually does not.

Warning though- if you’re ever thinking about moving, some areas won’t allow two separate leases on one property which could limit legal cashflow.

If this is a multi-family, are the utilities on the units metered separately?  

Here the more bedrooms the better so if you can fit 3 that’s great but the city or county you’re in may limit you to 2 depending on size allowed plus if you’re on city water and sewer vs septic that may play a factor as well because they may require a separate septic system which is $$$.

@Dylan Obrecht I've worked w some investors who rented out to college students, one of the benefits was increased rent because they charged separately for each bedroom.

I keep the houses we live in and use separate from those we rent. 

After you can push them all you can cut expenses (Separate utility lines and charge to the tenant?)

I'm just curious how some of you experienced property owners determine how much liquid money to keep on hand for a given property, if there are important reasons to keep that money in a separate or LLC bank account, etc.

If so, the hit up every single local bank because they will be happy to help (as long as you have good credit history and if you are just starting out then they are stoked to see a separate steady source of income and not all reliant on the new investments).