You must remember, though, that they will NOT produce new roots until the plants produce new shoots so your first priority is to keep them hydrated until new growth starts and many people put them in a bag with a small amount of damp sphagnum moss, blowing up and sealing the bag and then leaving it somewhere warm out of bright light until new shoots and roots are seen at which point they can be potted up as normal.
It is important to remember that Cattleyas need a cycle of wet and dry even during their growing season, and should always be allowed to go quite dry between waterings. Soaking and drying seems to be the key as does regular repotting.
there is no definite answer as to how often to water, all i can say is do it when they are dry (though if they are real babies they will need more constant moisture and warmth). Remember, Cattleyas are one of the most seasonal orchids there are; if they are not growing, they are resting and can't use the water you are giving them.