What does extended mean? Doubles and stages/rebreather extended? Of course, cold, is different for everyone.
I did (3) hour plus dives with a 45 minute SI between them in an old 3 mil full suit and a shorty underneath. By the end of the third dive, I was a little cold...but not bad. That's without any hood or gloves. If your diving dry, unless your extremely cold natured, I would think a minimal hood wood be sufficient...if any at all.
Are people from Minnesota, divers no less, even allowed to be cold natured? I would think it would be hard to run from the polar bears and abominable snowmen if you were shivering...
If your doing 2 hour plus dives, you might throw a 3mm or hyperstretch hood in your bag...it's not like it's hard to pack. If you need it, it's there. Get ready for some beautiful dives!!
Good luck, safe travels.
Jay