So I got the package of rental forms from WI Legal something or other, and on the initial agreement (M-M) I only required tenants to pay for "water"; not fully realizing that the Milwaukee water bill also has "sewer" and "muni" charges - which are far more than "water". 

Do you have experience renting remote vacation properties, and if so what is your experience and what are the key elements in your mind in making a great one. 

If so, was the second lien from part "1" a home equity loan or was it part of the original loan package?

I like 4plexes because of the "neat package" of financing almost identical to a SFR.

AMFAM is the one that says all perils on their elite package (but it was $150 higher).. so there is $150 difference.. may be for a peace of mind, I shouldn’t worry about $150 higher one

Profile and great packaging by your loan officer will get this done.

But even that aside you could look into commercial financing on a package of homes or package a bunch of houses together under one portfolio loan.

What data elements are required to submit on a pre-approval application?

@Matt Gregory the main element I would ask you to think about here is that a HELOC is designed as a temporary loan. 

Cleaning - you can still negotiate a package deal with the cleaner (if we give the contract for cleaning both buildings, we need a discount).