Ghostheart Animal Companion investment

[Phatrollerknight]

Which passives do you still generally want for them compared to the normal AC? 

[limaxophobiacq]

Wrong board (ghostheart isn't in PoE1), but generally you'd go for Vicious/Protective/Stalkers Link and Predators Sense with ghost heart, the big advantage of the subclass is you don't have to invest much in the companion and can just 'fire' it at your target. You certainly don't want any of the healing powers since it's cheaper to just re-summon it.

[Chaospread]

Totally agree with @limaxophobiacq. Don't invest much on ghost heart companion since it isn't always on your side, it must be summoned spending bonds and bonds are no infinite.
That said, it depends if you want a little tank as companion, so you want to choose Resilient Companion and Protective Companion; otherwise, if you wanna a "off-tank"/"damage dealer" companion go for Vicious Companion, Merciless companion and/or Predator's Sense. Stalker's Link is often good whatever style of play.
"Shared" abilities such as Survival of the Fittest and Superior Camouflage are always good because they are also character's abilities.
Distraction Training is not worth for a GH.
Don't spend many points on animal companion as a ghost heart: you are spending points in abilities that you are going to use a limited amount of time in combat: better to use points in others passives.

If you are investing more than 3 passive in AC companions, start thinking about whether it wouldn't be better to change subclass, unless you are trying something particular and/or limited to some encounters (i.e. megabosses).
You don't ask for active but usually i don't take actives for GH's AC: you have to spend bonds to summon you AC, if you spend also bonds in abilities... you'll waste all your bonds! Maybe Takedown, Master's Call and their upgrades can make a point, and, for sure, healing abilities is a no-brain NO, as limaxophobiacq already said.