Well, 100% both are male!!
Your orange micky mouse platy is male, even a female couldnt tuck her fins up quite that well!! (though you can try for more photos!).
Your other is just a young Swordtail, Swordies grow their tails at different rates depinding on their dominance, half to two thirds of male swordtails dont get their swords in the shops because theire are so many males in the small shop tanks.
It is fairly easy to tell between Swordtails and Platies but its hard to explain, its from experience of seeing a lot of both.
The swordtail has a wider/flatter face and is much longer in the body than the platy, also he stripes down the side isnt something you see on platies (not pure ones). Swordtails, male or female, are generally a lor longer and more streamlined than platies.
You are right in that you can get Brushtail platies with a small spiked tail but this is some fancy name for a hybrid. TBH most platies and swordtails are hybrids these days, same with guppies and endlers (all these fance scissor tail/pastel coloured guppies blah). Breeders and retailers are being pushed and pushed to come up with more and more bigger and brigher coloured livebearers and this is the results we get.
Oh and your little baby is a girl... congratulations
(dont know how you ended up with a baby, it is possible for livebearers to change sex but more likely it ended up in the bad when you bought a plant of fish from a shop and it got put into the tank!)