Dalmatian is definitely female, and may be pregnant. If she is, I'd say she's got at least a couple of weeks to go, because by the time she drops she will look like she's ready to explode. As noted above, even without a male present she can become pregnant several more times (they store sperm). Pregnancies last about a month.
As for the black mollies - hard to tell. The first looks like it might be female, the second looks like it might be male, but in both cases I wouldn't say for sure based on those photos.
Here's the key to id gender: fry of both genders and adult females have a triangular shaped anal fin below their vent, as is seen in the dalmatian picture. Adult males have a long, slender anal fin that points backwards, toward their tails. This is also called a gonopodium, and is the way his sperm are delivered to the female. When mating, the male will insert his gonopodium into the female's vent and sperm will flow down the "chute" into her vent, similarly to the way chutes on concrete trucks deliver wet concrete to the desired location.
The gonopodium starts to differentiate a couple of months after birth. Prior to that, all livebearer fry appear female.