.Can I give one object two behaviors? Say pathfinding and top down movement.
yes, an object can have several behaviors, but some of the behaviors influence each other and produce unintended results. Top down movement and pathfinding will have problematic outcomes if you use them together at the same time (the question would be anyway, why you want to use both of them: one is for active control, the other one lets an object move and avoid obstacles without direct control).
The same applies to combining pathfinding with the platformer behavior or the physics engine. Physics engine and platformer behavior is also not a working combination.
But there is the option to enable/disable behaviors in the events and if, for some reason, you would activate the pathfinding at some part of your game without the top down movement and vice versa it would work.