All the options you have shortlisted are decently good city bikes, and since your priority seems to be pillion comfort for your partner, sticking with bikes like the Honda CB350, Honda SP160 and Royal Enfield Hunter 350 would be our recommendation.
Coming to the matter of taking your newborn child on the motorcycle, purely from a safety standpoint, we would advise you to wait until they grow up and can sit on a motorcycle unassisted and can wear a helmet comfortably.

