As long as you don't use more then a 28T cog, a Sora rear derailer will work. However, any Shimano shifter will shift a Shimano rear derailer. The rear derailer isn't really speed spefic, the shifter controls how much cable is pulled each shift and how many shifts is performed.
The front is a very different story. You may not be able to use a chainring bigger then a 48T due to frame clearance.