How should I respond to questions? In third person or to my child?

However you prefer! There's no right way.

Let's take this sample question:

"If you could freeze time with Luke, what moment would you stop on?"

Here's an example of how you might answer this question in third person:

Any time that Luke is snuggling in my lap. I could be happy in that moment for a lifetime.

If you prefer, you can write directly to your child:

Any time you are snuggling in my lap. I'd be happy with you right there for the rest of my life.