The 'glass and a half in every bar' has been around for a very long time and means there is a glass and a half in every half pound of milk chocolate - or in today's currency 426ml of milk in every 227g of milk chocolate.
How you equate 'in every one' to be a sexual reference is beyond my ken and there is no sexier chocolate advert voice than the caramel bunny's - Miriam Margolyes. That advert gave me a very useful lesson, never arrange a blind date based on the voice at the end of a telephone :D
It is dark and rainy outside the shop because we all know a bar of chocolate can cheer up the foulest of days.
The kind shopkeeper gave the little girl her trinket back because she looked at it longingly after she handed over all her treasures, it is obviously her favourite.
How you can even think about casual sex in relation to the little girl is creepy.