Just got a pretty nice haul from the first dragon lair with 2 dragons that I've encountered so far, and wondering how much better it can get.

My primary hero's a Warrior and my second one's a Scout :)

Also, can there potentially be more than 2 dragons in a lair? Would be interesting to take on a half dozen....

7 dragons is a max. My best was from phoenix cult -egg and 3 red items with 2 purple

My best I got from a 5-7 Dragons Lair.

In New Horizons I got 2 of the same red item just in the spoils. I thought that was unusual.

In the campaign, what determines the difficulty of the harder lairs? I thought the hardest ones would be furthest from any stronghold, but this was on a Small map (i think, defense actually) while I've only seen single dragons on even Large / Big once until now.

Do lairs etc get harder as the campaign proceeds?

Campaign artificially lowers power of all neutrals, both in sites and provinces.
The further - the less, around 15+ astral turn this is mostly gone.
You can get strong dragon site through random event "Dragon appeared", power of this site increases for every 50 turns before creation. (probably I worded that wrong - I mean that this event at 51 turn can generate 2 dragons, at 49 - only 1)

Ah, I see, thanks! So those are the sites I should pay attention to :)

And I just recently realized there is a "locations" view of the provinces. Just wish there was a way to order by Province Name since it's really hard finding the province an event just happened at when you've got 100+ to go through....

Even more I wish during an event it was possible to view information about the province in question, particularly what guards, if any, I have on that province - that would definitely impact the choices I make (harpies, demonologists, etc.)

During event province is selected, so you can see image of its guard. For novice it isn't very helpful (as with egg exchange for unknown artifact), but with some experience you can estimate outcome.

Different impact on province mood and karma.

Which one's worse? I guess telling them "Attack if you Dare" and them winning is worse for mood and karma?

giving them what they want gives -2mood, no impact on population size, -6 karma.
"attack if you dare and losing" -1mood, -population.
giving gold +5karma, they don't take it anyway.
executing deputy - universally -3karma, -2 corruption.

Took me a long while to realise that there is the full province information at the bottom of the screen, too. The first 100 hours probably I made decisions wishing I knew more about the province. Eador event windows must have some weird attraction that blurs out their surroundings.

So "give gold, attack if you dare" is best for karma and only costs a little mood and population (so a little less gold per turn), ok, thanks :)