So they've got 6 people, but 3 brooms, so they try to double up people on each broom. But the brooms are too small for two people, so they make larger brooms from trees. Shouldn't they have 6 brooms now? They could just each get their own broom again.
I guess it's possible they just took the bristles from the old ones, but it looks like they just gathered twigs for those too. They also could've just made one extra broom instead of 3 (since Marius + the succubus can fly).
@464we Going by the "embarrassed" caption probably I Want To See You Embarrassed, another manga TL'd by this group.