Do I need to upgrade my alternator with these fans?

First off 210 isn't hot, and 210 after running sitting still for 20 min ain't bad at all since the viscous fan isn't doing much at those RPM's.
Also keep in mind that those fans are only going to run when stopped and the temp goes up.
Stopped and idling in the rain with the wipers, headlights, tail and markers, all your dash lights and the heater going might be an issue, but then the fans probably won't be running much at all in that kind of weather.
The MAD bypass will help but the engine will be at idle and not producing much charge anyway.

Yep, it's a definite who knows.:D

FYI, it's one of the reasons I run LED's in everything I can but I only have a single 20 amp electric fan.
I also have relays supplying my headlights, so I don't have that drain on the cabin wiring either.
Everything else is really close to what you are thinking you will have, and I don't have ANY low power problems even with everything I listed above.