Normally, a group like this will quickly find a replacement roommate if one moves out- just be sure they also pass your background check and you get a signed statement from all of them agreeing to the new arrangement and detailing how the security deposit is handled.

My first instinct would be to arrange them to be 2x 4-plexes (rather than 1x 8-plex), or is that already a given?

Hint: it wouldn't.I assume the note you're buying is from a person (not a bank) since any bank note/mortgage would have a due-on-sale clause preventing you from engaging in this arrangement. 

Where can I look for resources on business arrangements?

Is there a fair arrangement that could be worked out with a broker in this scenario?

Usually when an appliance breaks down and needs to be replaced I would arrange all that and no issue.However I went on a month long vacation outside of the country, and a refrigerator broke down. 

It was a pain in the *** to get this fixed but I finally did, thanks to some friends who were kind enough to help me re-arrange the entire garage and get the car in there (a whole day of work for 3 of us).

I let the broker know and he calls to arrange a viewing...

. #3: What about your OWN mortgage/rent arrangement?

However if you ask her to go through them, you guys should come to an arrangement of some sort.