Where the trip stands
What each person paid the group, minus what they consumed. Positive means the group owes them.
The short version
Repayments recorded
Partial payments are fine — record what actually changed hands and the balance moves by that amount.
Record a payment
Money that has already moved. Fatou left after day 3, so her share of the chalet was only three nights.
Add an expense
Amount in whatever was actually charged. Then say how it was really shared.
Everything spent
Fewest payments to close it out
Computed from the current balances: each transfer moves as much as the smaller of a debt and a credit, so nobody pays out twice. With these numbers it is the fewest transfers possible.
Every balance, again
Add an expense or record a payment and this list, and the plan above, change immediately.