In principle, you don't need two copies of the device library. You create two instances of the same object.
You may need to fix any problems this causes with the class library if it is not written properly. I found the library for this device is not very good, so I fixed it.
The other problem is, you tried communicating with the two devices, and it didn;t work out. You need to solve one problem at a time. Try connecting just one device, and make sure it works. Then try just connecting the other device, and make sure it works. Then you know for sure, each of your devices is good and not busted.
Then try connecting just one device to the emulated I2c, and see if that works. And then the other one. Then you will know if the emulated I2C scheme actually works.
Only after you have done all those things, should you try using both devices.
Your alternative plan is to use a different device, such as the MS5611, then you don't have the I2c address problem.