AI control both NPC and car

I want to make the NPC do the following tasks: From certain point move to a car and enter the car (with animation), then the car move in a pre-determined path.
I found this tutorial to get some ideas, but it’s for player controller. I’ve followed some AI tutorials on YouTube but most of them focus on character AI.

I mainly have following questions:

  1. How to change the pawn the AI
    controller posses?

  2. Since I want the
    NPC to perform continuous behaviors,
    it’s easy to have a intension to add
    certain tasks in BT, but the BT will
    be used for both NPC character and
    the car and this seems impossible.

  3. What other things should I consider?

  4. Is there any tutorial that might be
    helpful?

  5. I’ve seen several vehicle
    AI plug-in in the Unreal market, is
    there any recommendation that might
    be suitable for this task?

I’m a beginner for UE4 so please forgive me if I make some silly mistakes or have any misconception.