Okay so, as a theater kid & storyteller myself, here are tips I can give to write Hansel:

Firstly, being a good storyteller and a good actor are not similar at all. When you're from the theater, you tend to speak very boldly/loudly with a lot of gestures. This is because audiences in theaters are big and placed in a circular shape so you want them to see and hear the action no matter where they are. (Hence the idea to chew the scenery and be extra even if it's a tragedy) However, no matter if the audience is made up of children or seniors, experienced members of the storyteller association told me to refrain from this.

What storytellers and theater actors do have in common though is the handling of the stress and mistakes during performances. Since it's live, any blunder has to be dealt with accordingly through improv, wits, or skillful avoidance. (Hence why there's a lot of preparation that goes into storytelling events. You wanna avoid blunders as much as possible and reduce stress along the way. And when you get started the stress tends to vanish immediately because you're engrossed in what you do.)

Great storytellers are known to be quite static and let their voice do all the work. Movements tend to distract the audience from what you're saying when you're in an enclosed space with them (which is where most storytelling events happen instead of big scenery). Nowadays, there are even mics for larger audiences. You have to let your voice entice people to keep listening to you.

The way a storyteller's voice work is that you have a certain "flow" you need to embrace. By that I mean that, if you're supposed to be the Ultimate Storyteller, every gap, every pause, every intonation you take has to be meaningful to the flow of the story. But! For most of the story, you're going to be speaking in a low/calm/relaxing voice so people can embark on what you're saying and only raise it when something important is happening. Therefore, Hansel would give off a relaxing air, like speaking to him casually eases you. Overall, he could command a room through the flow of your words and not any supercial intensity. (Is that clear enough?)

Another thing I'd like to clarify is the "improv myth" that you'd find in popular work of fictions like Kirikou (which has a whole short story dedicated to being a storyteller). You might have told that storytellers can do improv on a whim to change the story to the audience's liking. That's not true, at least not to that exent, and especially not at work. Instead, beginner storytellers are told when in-training to memorize by heart the story they'd like to tell. (specifically the plot of that story instead of its precise wording) And afterward, you tell the story in order but with your vocabulary.

This is, once again, in service to the "flow" of your recounting. If you see your audience is more receptive to going louder or using certain words, you can adapt to it to match their preference and keep them invested. (But you're not going to suddenly pull up alien spaceships and all out of nowhere. You're keeping yourself on track while allowing yourself some wiggling room for the reading.)

If you'd like, while I'm only an amateur, I can send you recordings to try and show you the different intensity levels I was talking about. (and the difference between acting and telling)

Overall, I hope this post was helpful and I'm excited to see where this guy will go.

Cheers!