should be an interesting build. Since you are on the shore of Lake Erie, maybe folks do not realize what the winters are like. I was born in Erie so.... I gots memories!
Here is a good pic of what lake affect ice spray does to locations along the shore line:
I do not think any wiper or heater could withstand such an onslaught. For sure, not any PTZ. Would have to be not only IP67 but..IP2000!
You would have to find a way to heat the surrounding area before ice buildup becomes an issue. That Ventech box above may protect the camera, but ice will build up around the heated structure as well.
End result may be that Mother Nature wins, regardless.
The camera would have to be inside a protective waterproof shell, for starters, out of the sun for summer time. Just like the Ventech. Maybe you could add a tiny fan that runs off 12v for summer time purposes. The RJ45 wiring connecter would need triple dielectric grease & triple heat-shrink-wrap parts. Even then, ice will get in there eventually. Best to leave the connection inside the camera protection box or through the wall to the boat house.
For ice building around the area? What about those 12v/24v anti-ice gutter heating elements? I know they are used up at Lake Tahoe for snow duty. Unsure how would fair towards ice duty.
What is the purpose of the camera? For pretty view of the lake? Or to keep eyes on boat & launch area? I would put up some wind barrier (metal, not wood nor plastic) to help deflect ice spray.