Re: If you use flats with a heavy wetter, how do you make it work?
Are you planning to line dry? I'm hesitant to bring hemp because I understand that it doesn't dry well in humidity above 8% (per Mother-Ease and Wadoozle).
If you are buying any new flats, I have read that unbleached are more absorbent than bleached.
If fleece jammies are too warm, what about an inexpensive upcycle wool soaker over her usual pocket or cover? If you use roomy 1-piece pajamas, this should work well for insurance.