I feel like [name_m]Spencer[/name_m] is far to neutral (arguably leaning more masculine) for the sibling options.. I’d just name the siblings other neutral names, (i.e. brothers dylan & cameron and sisters rory & quinn) However if I had to choose from your lists.. brothers [name_m]James[/name_m] & [name_m]Ryan[/name_m] and sisters [name_f]Charlotte[/name_f] & [name_f]Emma[/name_f].