How does the "Penthow" card work? All 3 of his primary stats are highlighted, so does this mean that each player can choose which one they are competing in, or do you add up all of the numbers from those 3 stats?

Also, now that I've posted a few of these - is there a rules FAQ that I should be referencing?

Your first guess - each individual player chooses which one statistic they compete in.

Source: FAQ 1.1 p. 3

And yes, there is a FAQ:

http://www.boardgamegeek.com/filepage/49001/arcana-faq-v1-0

I have just myself recently got this game, and I must say it looks promising.