I had already talked about those but:
Martine is possessed by Laguna.
Zone is possessed by Laguna.
Watts is possessed by Ward.
The Forest owl member sitting on the couch is possessed by the old Adel resistence member which was on the prison with Laguna.
The Forest owl member controlling the train is possessed by the guy guarding the Lunatic Pandora facility which is also a member of the Adel resistance member.
The Forest owl member standing next to the previous one is possessed by Kyros.
The floating guard who attacks Squall on Galbadia Garden is possessed by either Laguna or Kyros or Ward (I don´t know).
Biggs and Wedge works for Laguna secretly.
They are responsible for the maintenance of a primitive version of the junction machine.
There is an agreement between Laguna and them in which they shall use the machine (on Galbadia) to send Laguna and company´s counsciousness to the past.
Maybe Laguna told them Hyne´s secrets and they decided to work for him.
Of course they pretend loyalty to Deling(Hyne).