The dynohub should have some resistance. This is not to say don't regrease them, but they don't spin smooth even when properly greased... The magnets create drag.

I believe the proper fenders would be Britania, but those are even tougher to find than Bluemels. Bluemels do turn up - I've gotten three pair for around $50 bucks each over the years. They turn up. I just got a brand new front one for $10 off ebay. I've bought a whole bike to get a set of fenders, then sold off the bike.