My DP and I have separate blankets, that way we can keep them away from DD2 easier by tucking them around ourselves independently (hard to explain, hope that makes sense) which might be an option? We also have the cot pushed up against our bed with that joining one side off for extra space and DD2 begins the night in there.

DD2 has day sleeps in her older sister's bed (toddler bed) usually as we keep our bedroom closed up during the day so that everywhere accessible is 'kid friendly' for when I need to pee lol so can't help much in that regard.