Interesting...

[eternasky]

Spirit Companions can't be flanked because they're not creatures.

Q: Can the spirit companion be flanked?

A: No. This is a bit of complicated reasoning, but to be flanked the target needs to be a creature as defined by the PHB 57. Your SC is not a creature and therefore can not be flanked.

[elijin]

Can they flank?
If it cannot be flank, but they can flank seems quite flawed.

[eternasky]

cannot flank unless the stalking spirit power successfully hit some creature. (which my one dun have)

SCs are conjurations, not creatures. So no charges either. They're proxies for the Shaman and attacks originating from the SCs take LOE from the SCs.

Shamans are required to maintain LOE to their SCs in close burst 20 or they will go poof.

But I kept allowing SCs to be flanked in the past cos i tot flanking affects everything, den i realised it's only to creatures.

So fun fact

[thedungeonmaster]

That's why 'L' sticks to his wolf companion...