Need some advice for a new Campaign I'm running for 3 new players including a child.

Party is 3 new players 2 druids and a Pyro wizard (Criminal with high dex). So to balance it out and help give them some in-game guidance, I would like to create a character to help them but give them the spotlight.
One of the druids is my 7yo daughter as she likes to turn into snakes and bite people. So my character will be her dad and the party's guide.

I'm planning to have them start in a small wooded village as a introduction, then travel to a Hogwarts like magic school and then eventually they get a dragon egg they need to protect and give to its parent (exploration arc) (Dragon prince style, Hooray for Plagiarism)

What do you think would would well for my character to help them along but let the players take the lead and learn and have control? My daughter and I will also secretly be a changeling so advantage on charisma checks when I'm needed to step in.

1. Artificer Cartographer
   Support, buffing initiative, faery fire teleport to allies and short distances and is a new class to try but party is squishy. Wants to map the world.

2. World tree Barbarian + Alchemists Artificer
   Tanky, with magic weapons and armour, can make potions (drink in rage or give to party), world tree five temp HP to ally and introduce multiclassing to the new players but will take longer to get to milestones (extra attack, subclasses etc) (level paralysis) Being a natural herbalist would work with druids natural theme and maybe the Wiz study and fire theme. Will also show off re flavouring ie rage is drinking a berserker potion.

3. Battle Smith
   Defender can tank and support, can make magic gun to support and can tank well. The defender can be a cute fun and playful. Very strong.

4. World tree barbarian (Crafter background)
   Tanky, share HP, can pull enemies late game teleport, would not take spotlight from others with mental stats. Also Nature theme and would add strength to the party. But is not a new class or subclass.

I have the base 2024 books and the new Eberron Forge of the Artificer book.

Thank you in advance and any and all ideas and feedback including backgrounds you may have will be most welcome.