Does Lor have a sewer system?
I would think so.
How extensive is it?
Never gave it much thought to be honest.
How navigable is it?
Your standard damp, moist, slimy, dark run-of-the-mill sewer I'd say.
Is there an in-game map of it (that is, does the city council has a (semi) detailed map of it)?
Probably not anything detailed. Lor wasn't built in a day after all so it grew over time and I envisage things being added as needed and not on any planned or structured basis.
Is there access and egress to it?
I would think so, there'd be drainage pipes into the harbor, people with access hatches from their basements, grates, etc.
