I haven’t found the need to over-track other players. You just get a sense of have they bought a place of power, how many actions are they taking, and that provides the pressure you need to make the game exciting. In between rounds you check how many points everyone has, that’s the only time you really have to look closely - and you don’t do that until round 4 or 5 anyway.
I don’t have a compelling reason to definitely play it at more than 2, but I’d recommend not worrying about it either 
Two (or one) is definitely my favourite.
Except - that lovely round island you get with three players is just so satisfying. Perhaps two players running three spirits is what I want!
Yeah - if it had been higher on my list it would have been subject to more scrutiny. Spoiler, a future week will have co-op/campaign/scenario type games so this probably properly belongs there.
My husband and I have done it two-player three-spirit. We do it as his, mine, and ours and typically figure out what we can each do with our own then work together to use the joint one to fill in gaps, making any changes to our individual plans as needed. It’s fun.
That does sound really good - we’ll have to give it a go!