Minikits in order as they appear:
Rescue Janine Melnitz
Foyer Throw Down. Use the Relic Detector to let the pipes for the drone appear. Use the Drone to rescue Janine.
Foyer Throw Down. Push the luggage carts onto the right colours.
Ball Room Blitz. Destroy 5 paintings. Use either Relic Detector or Magic to let them appear.
Ball Room Blitz. There is a big green wall, where Slimer was hiding behind the big painting in the back. Use X-Ray to open that door. The Minikit is inside.
Something Big on the Horizon. To the right. Use Technology and solve the card match memory puzzle.
Something Big on the Horizon. Destroy the cracked wall with Strenght, destroy the boxes and shrink and grow to get the Minikit.
The Traveller. Move around the battery with a plane (flying vehicle) and shrink to get into the pipe to get to the top.
The Traveller (Dana's Apartment). To get here you need to discover the Laser Deflector Plaform with Relic Detector, deflect the hound's lasers and go through the portal. Use Grapple to be able to grow/shrink to get the Minikit by pressing the button in the pipe.
The Traveller (Dana's Apartment). Destroy Venkman's painting with Laser and Drill through the wall. Fight 3 hounds and the Minikit is yours.
The Traveller (Dana's Apartment). Destroy everything and set up the colour platform and the pattern with the help of Magic. The evil telly is destroyed and you get a Minikit.
The Traveller (Dana's Apartment). Destroy all the red kitchen items to build a ghost containment unit. Catch the ghosts from Minikit 9, put them into containment and get the last Minikit.