I think the chatter is just little high mileage slop in the engine...until the oil makes its way completely around the engine. It generally will only do it if the car sits for more than 12 hours and then only just at start up before getting quiet. My best description of the sound would be a pushrod wobbling around a bit in its guide.
The film on the windshield gets more noticeable when the inside glass isn't cleaned for a couple of weeks. It doesn't have to have the fan on heat or high to get foggy. I'll get a good workout some mornings and when I get in the car...my bodyheat will make the film fog up. I can take my finger and wipe the film off the glass and there is clearly a difference between clear glass and foggy film (hope that makes sense). But to answer your question...yes, the window will fog when I turn the heat on high (this is when I hear the persisting groan from the engine bay). The window will fog before clearing...but I can still wipe my finger or cloth on the glass and get a clearer view.

Just for clarity...you mean complete overhaul of the cooling system...right?

Funny how these cars are...I always have a project on the horizon...then I run into a real problem

Thank you again...you're $.02 is appreciated...