MultiFamily Collections is a different kind of collection account. There are a lot of variables to it- like, your resident qualification criteria, like your company collection policies, like the demographic make up of your portfolio, the way the accounts are submitted, etc. As Davin referred to below, speaking to a knowledgable collection expert like himself, me, Tracy, Carol or Joel (and we all work at various agencies across the country) will benefit you the most in understanding what you can expect out of your specific debt portfolio.
As for the question regarding, placing an account with multiple agencies. Yes, it is a violation of the FCRA and can get you and the agencies into trouble.
All 3rd Party Collection Agencies, like the one I work for, all have to follow the local state and federal rules/regulations of the "Alphabet Soup" gang, including the FCRA, FDCPA, TCPA and the CFPB... just to name a few. I can tell you that things have changed dramatically in the last 9 years I have been working here.
Multifamily debt collections, although it appears to be a very simple process, it can get complicated very quickly! I hope this has helped shed some light on the topic of MultiFamily collections.