I think I saw a discussion about this on a bowfishig link in the past and the concensus was that you can possess both traditional fishing tackle and bowfishing equipment in the boat at the same time. The original poster noted that he left one in the car while using the other and switched to do night bowfishing and felt it was a waste to have to go back and forth.
The one note in your post to be aware of is I do not believe that WI allows spearing of fish for the general population so I wouldn’t have a spear in the boat.
This is my recollection of that discussion, but ideally you would confirm this with the DNR because they are the ones that do enforcement.
Dave