Welcome to the forum. I'm sorry you're having this issue. The first thing is to stop the water spraying. All it does is antagonize the cat and not in a good way. It is not the way to change a cat's behavior! Second of all, cats are very intuitive and their smell is 14 times stronger than ours. Your wife may be exuding hormones that the cat can pick up on. This may change after the baby is born. The best thing is a firm "NO" and for your wife to make sure she is wearing something to protect her ankles and feet at all times.
In some cases, adding human babies changes the whole perspective with bengals. They are highly social creatures and bond solidly with their owners. Many accept new babies as their own. Others can be jealous. Many bengals are rehomed for that very reason.
I would suggest some Feliway diffusers and put the diffusers in various rooms the cat goes into. It is supposed to calm them down a little. Jackson Galaxy also has Spirit Essences which are herbal treatments for various behaviors.
http://www.spiritessences.com. See if there is something there that might work in your case.
You are about to bring a brand new baby into the house -- a new smell for your bengals. It's difficult enough to care for a new infant but you have a toddler too. This is going to make for a very busy, boisterous household. The kitties are going to require attention and it may be you that has to step up to the table give it since your wife will need to tend to the children. I'd see if you could bond more with Charlie. You feed him, you do the chores for him that your wife would normally do. See if this helps.
Congratulations on the baby.