A major element of co-mingling is time. Since this is relatively recent, the money sitting in the dormant joint account is not clearly marital property, not clearly individual property. This is something that will need to be worked out. So yes, you can use it as leverage to win concessions elsewhere.

Once you've worked out marital vs. individual property, the rest is simple. Wisconsin is a community property state. Anything deemed marital property will be split 50-50.