I'd like to know if it's viable to put points into 3 or more active skills and 3 or more passive skills, or whether I should place emphasis on one or 2 skills in each category. Thanks.

Tough to say-- we really don't know yet what the difficulty thresholds are going to be like in the game, or what buffs will be available from food, equipment, etc.  That said, I'd be shocked if any kind of skill distribution led to a character not being viable. 

 

My intuition in thinking about the system is that the best choice might be to make the main character something of a generalist, while the other partymembers specialize more. 

See this post for some information regarding party assist thresholds: https://forums.obsidian.net/topic/96978-deadfire-sneak-peak-with-josh-sawyer-wed-april-25th/page-2?do=findComment&comment=2000225