According to the RR database, all Dakota County public safety agencies now use the statewide ARMER system. ARMER is a P25 phase I multi-site, trunked radio system. If you're not up for programming the newer radio systems by hand, I would suggest that you limit your consideration to scanner models that rely on a pre-programmed database - such as the Uniden Home Patrol, or other models in the HP series.
The Home Patrol scanners are primarily intended for desktop use and have large, easy-to-read displays. The HP I will work for the ARMER system but is an older model. The HP II is newer and will work on P25 phase II as well as phase I, so it offers a bit of future-proofing. The other HP models are your typical mobile or portable scanners. Like the desktop Home Patrol models, some will do P25 phase I only and some are both phase I and II capable.
Disclaimer: I am not familiar with the ARMER system and do not know if any of your desired targets use encryption. No scanner is capable of monitoring encrypted signals. Perhaps it might be best for you to ask about the statewide ARMER system in the MN forum here on RR.
Best of luck,
John