I agree, he wouldn't agree to take the kinds unless there were very strong reasons for them to be taken and maybe they weren't snacthed at home? I can't see the kinds or Methos inviting anyone to come in.
So it has to be a situation where he thinks taking the kids along will be safer for them and for him... maybe Belle gave the order they were to be taken unharmed to her?

A scene in the stronghold would be pure win! especially if at the start before the "hostages" get there Belle Morte is doing the evil speech thing and humiliating everybody else.
He would say to her that if she really wanted to fight Death all she had to do was find him
and she would be completely exaspered and say something like "What do you think i have been trying to do for the last few thousand years??"

and there will be many issues to be solved especially with regards to what happened to his brothers and just "why did he cast her aside?"