I tend to agree that there probably should be some redundant escape system in place in the event that a saucer separation is impossible. In the very least there sould be something in the secondary hull (like the pods in TMP) for the engineering crew to use to escape if they're cut off from the primary hull and the shuttlebay, or the saucer has already separated. Now, since you used the Constellation as en example, what if a connie had sustained that sort of hull damage, main power & long range comms offline, life support failing but they're in range of a M-Class planet? Sure they can separate and make it into orbit, but with that sort of hull damage, an atmospheric entry without shields would be disastrous. Escape pods could make the drop and with them everything the the crew needs to survive long enough to await rescue. As you say, the saucer has a surprising amount of floorspace, so there should be enough room to fit in say forty three, ten person escape pods, about 6x4x4m in size. As for Rand's perfume, if they have the chemical technology to create and mass produce new an complex medicines, I don't think scented water would be much trouble. For anything more exotic and authentic, that what starbases & traders are for.