Bit of a complicated question- multi-component animations in sync?

I have a character, essentially a varient of an Alien facehugger. I've managed to animate all the parts successfully in Blender so that it leaps onto the back of a human character, coils it's tentacles around said person, and reveals a nasty proboscis that limpets on the head. All boned. Each object is separate, the limbs, the proboscis and the body. I've imported all the relevant fbx animations and have an Animator Controller on the main prefab that contains all of the parts but can successfully only get the body part to leap onto the back, leaving the arms and the rest unanimated.
My question is, how can I set up my single animation controller to animate all of the parts at once? Do I need several controllers? Can I create a single clip that mixes all of the animations together and drop that into the controller? Thankyou. I can supply the test file if necessary.