Bayanet is talkgroup 2818. Be advised they are at most times encrypted and on your 996T as mine is as well you'll hear about a .1 second blip of encrypted sound and the scanner will continue to scan from there. They do at times will have one side of the conversation be in the clear, but the other side will be encrypted. Most times they are encrypted.
I am directly familiar with Isabella county as I'm in Bay County and can get Isabella off my outside antenna and routinely tune it in.
I have recently gone through my scanner setup and had to delete a bunch.
They aren't as stated 'encrpted', but are using a using a system no scanner can decode.
If it wasnt for having the PL code programmed in for those frequencies you would be hearing the annoying mototrbo sound.
As an example, If you know how to, remove the PL tones in your radio from those you dont seem to get now and you'll hear the following.
MOTOTRBO Digital Sound Sample - YouTube
at that point you will need to use the lockout button as no scanner made can decode it.
With that said, it can be done using dsd software.
Wiki -
http://wiki.radioreference.com/index.php/Digital_Speech_Decoder_(software_package)
Forum for it -
Digital Voice Decoding Software - The RadioReference.com Forums
Even then if you do succeed with that, they still 'could' be encrpted and then you'll be out of luck.
I have looked over Isabella not long ago as well on the database and unfortunately for scanner listeners out that way,
in the neighborhood of 1/2 the radios in the county and city are using Mototrbo, aka DMR - Digital Mode Radio.
I.e. Mt. Pleasant city fire, township fire frequencies, CMU facilities, the casino, ITC buses.
The WPDZ292 154.875 is currently still not using mototrbo thankfully as of now.
The database is based upon users who send in submissions so that the database listings can be updated to better reflect out of date, new frequencies, etc. If you go to the Isabella page, click on the 'Submit' tab in the near upper right any info you can help out on, which in turn helps you, helps all others looking for the same info too!
RR Database Submission Guidelines - The RadioReference Wiki
Isabella County, Michigan (MI) Scanner Frequencies and Radio Frequency Reference
Far as the digital side on the talkgroup listings, actually none of those listed above I have picked up personally. I may not be close enough to pick up a tower (aka site neighbor) that carries those if they did get used.
IMO in all these years they should have been heard at some point never the less. To me those are valid talkgroups, but just not in use or are rarely used at this point.
I have seen at times talkgroups listed, but nothing heard for several years then it starts being used. I.e. Midland county talkgroup 1257 patch for MSP to be able to talk to Midland 911 VHF setup was listed for several years and became active only about a year ago.
One that is very talkative is the MMR ambulance 13062 talkgroup that handles Isabella and Gratiot