Define exposure? If they were kept in the same enclosure, they have it. If it was through handling, no stool contact, then chances are likely that the numbers they were exposed to were not enough to instigate an infection. This number of pathogens will vary from strain to strain, and is different among pathogens. I don't know what it is for crypto, it's likely irrelivant though. An example though, would be canine parvo virus. ~1500 viral particles are needed to instigate infection in a susceptable puppy. Roughly 5 million particles are released in a single shot of diarrhea.
Since crypto is a direct lifecycle parasite, keep things scrupulously clean, and try to get the stool out of the cage as it's coming out of the snake... or relatively speaking :/
Hopefully any crypto obtained by the snakes will be beaten by the immune system before they become infectious in number.
I'd recommend a 6 month quarantine and future considerations while considering these snakes possible "carriers" of low numbers of the disease. If memory serves correctly, there is not definative test to say that a snake is crypto negative.
Good luck, the first month will be the thoughest.
Ian