Idea help needed

So my party found the red dragon egg and the obelisk. 3 of them were next to the obelisk and activated it and where telephoned away.

I need to decide on a few things and prep for our session later today

1) the 3 that were teleported; where did they go, are they together, etc.

2) what to do with the 2 (both my sons 7 and 14 years old) who were left behind in chamber 14.

3) I know that the Warlock wants to hatch the red dragon egg they stored in the bag of holding. She rolled a mat 20 and figured out it needs alot of fire to hatch she told me if she's alone that's her plan. If that happens how do I play it in grack and what other fall out would happen?