You need a lawyer - the Michigan Bar Association can give you a referral.
If we do not have a signed fee agreement I am not your attorney and this is not legal advice.
For your specific questions about the motion you should consult an attorney in Grand Rapids who can evaluate the specifics of your situation.
Generally speaking in a divorce proceeding the judge will treat that pet like any piece of personal property and divide it up in a fair and equitable manner if the parties can't agree on how it should be handled. The judge may consider things such as who paid for the care of the animal and the conduct of the parties toward the animal in making a decision.