I have a 2 year old rescue, 3 month old puppy and 3 snakes. They will never be in the same room together and out.
You can fool yourself in that you can change animal nature and your snakes and dogs get along but all your need is one situation where snake defensively strikes at dog and dog defensively bites snake. If you think vets are expensive, you do not want to know the cost of emergency surgery for massive tissue trauma on a snake... if the snake survives a dog bite.