Assuming 3x of each:
Scourge - Passive is +3 Fort save. Minor, but always nice to have. Active is 6% double strike; useful for melee builds.
Bladefrog - Passive is 15% Fort; universally great, and almost makes up for playing Bladefrogs. Almost. Active is Repair spell power, only useful if you hate yourself and play Warfrog/Bladefrog.
Insect Thing - Passive is +9 MRR, universally great. Active is +3 Illusion DC and +15 Acid SP. Only truly useful for Sorcerers and Wizards, though anyone using GCS may find it handy to keep in mind.
GrimDark Edgelord - Passive is +3 vs Enchantment saves; universally useful, especially once the devs nerf Freedom of Movement again. Stance is +3 Necro DC and +9 Negative SP. Again use limited to a few classes that make use of Death/Necrotic spells.
CHAOS - Embrace the Madness. Passive is +9 Universal Spell Power, great for any casters or anyone who has some form of magic healing/damage, etc... Active is a Fey Step clicky, which is universally useful except on classes that get wings normally to bypass some jumping puzzles or get out of harms way.
Half-Ogre - Passive is +9 PRR, universally useful. Active is a sprint clicky. Also universally useful.
Razor Ramon - The passive bad guy is +3 Will saves, universal. Active stance is +1 THAC0 and damage. Useful for melee/ranged, but not critical.
Emo Edgelord - Passive is 3% Dodge, universally useful. Stance is a defensive buff if you get smacked upside the head while below half health; it can theoretically be useful, but I probably won't ever use it over another stance.
Morningglory - Passive is +9 Positive SP. Prozac. Useful for anyone using some form of positive energy healing spell/ability, which is nearly everyone after awhile. Stance is +30 Light/Alighnment SP, useful for Warlocks and Divines.
Kitty - +3 saves vs traps, universally useful (especially with evasion and stacking with the last IPL). Stance is +3 to trip DC, which I think isn't going to be picked over other stances.
Scoundrel - Passive is +3 Reflex saves, universal. Active stance is 30% striding, which is inherently universally useful until you get another source of striding.
Mostly, the passive abilities are universally good to have. Only Morningglory and CHAOS aren't directly improving your survival ability. And CHAOS has one of the more universally useful abilities in the game. If I was starting from scratch, I'd probably do the Scoundrel lives first for the striding (assuming no Quiver of Alacrity), then CHAOS, while the rest can be added in any order based on what builds I play primarily. If you play casters, might focus on the caster lives, melee it might be best to clear out Scourge, etc...