Looking for advice on a portfolio of multi-families

[Mark Swim]

I've agreed on a price with the owner of 3 different properties for an off market deal - one 8-unit apartment building, 3 duplexes on a single lot and 1 duplex on another lot.  I haven't given him the official offer to purchase, yet, and am looking for some advice on the following:

1. We've negotiated the price of each property individually.  Should I submit a separate offer for each property or lump them into a single offer?  Pros and cons of each?

2.  I will be financing these through a local bank.  Does it make sense to carry a separate mortgage on each property or lump them all into a single commercial mortgage?

3. The 8-unit and 3 duplexes are all filled with tenants from the same ethnic group and are a pretty tight knit community.  My concern is that when I need to turn a unit that my pool of potential tenants may be limited.  Has anyone dealt with this type of situation and what was your experience when trying to attract new tenants.