L.G.
14 1/2 months seems young to end the morning nap, although, I'm sure many kids do. However, many don't, so if your daughter still needs it, it seems like you should let her have it. I know you say it's "not an option" to have them on different schedules, but you can't force kids to sleep (no matter how hard we try!), nor can you keep them awake if they're tired. My sister has twins, and from day 1 everyone says, put them on the same schedule. But, it's important to remember that they are two different people. If you had them 2 years apart, one would probably have a different napping schedule than the other.
I'm not sure what your work schedule has to do with it, since if you had one child, you probably would not be trying to change what his/her body was naturally trying to do. Especially since most 14 1/2 month olds still take 2 naps. One can still nap when the other doesn't, even if they share a room. Probably better to get them used to that now, so that if they continue to differ later, it won't seem strange for one of them to nap without the other.