My current wetsuit is a Neosport 3/2mm jumpsuit in 3XL. It was inexpensive to purchase and fits me well, and I find it abundantly comfortable in 72 degree water without gloves or a hood. In general I don't get cold easily, and can recognize my limits after decades of living, motorcycling, skiing, and generally being outside in this climate.
I wore a 3/2 wetsuit on our dive in the Keys, last week, and I was freezing! No way I would describe that as "abundantly comfortable", dood! You must have been a polar bear in a previous life!
I think you're going to find that frozen lakes are pretty cold, even after the ice melts. Go with the most suit you can find and afford. No way you're gonna get too warm diving in the Great Lakes in a wetsuit. If you do, just jump back in!