There doesn't seem to be any definite pattern to allergies - some people have said they're better with Bengals than other cats while a few have said there's no difference. I think it's often the case that an allergy subsides after a while. My brother was very allergic to cats when he was young but now has a cat at home which he's OK with provided he doesn't get the cat's saliva on his hands so he avoids stroking it down the side of it's face and under the chin. He doesn't do any cat grooming or let it sleep on his bed either.
In the short term your husband and son could get some piriton or similar to help them in the first few weeks.
I'm glad to hear that you'll let them suffer rather than get rid of the kittens
PS Just to add that the allergy to cats is actually to their saliva and to glycoprotein which is excreted by the sebaceous glands rather than to their fur. That's why avoiding contact with their mouths can be helpful. Obviously cats wash themselves comprehensively which transfer saliva to their fur, hence people think it's the fur itself they're allergic to.