How to use all the space in extracted hard disk (remove leftover system folders)

Not sure if this will be helpful, but I just wrote a script to unlock and mount a core storage Encrypted Disk like yours for myself. I had the same problem where I could get the disk unlocked, but not mounted. I finally realized that I needed a command to mount it after it was unlocked.

In terminal, you first have to unlock the Encrypted Disk and then you can mount it with a separate command. For you, that would look something like this:

diskutil cs unlockVolume E2DB4126-C04C-4AE1-B1AC-CDFF0218D537 -stdinpassphrase 

You will be prompted for the password to the Encrypted Disk. After this, your drive will be in an unlocked and unmounted state, so you still need to mount it with this command:

diskutil mount E2DB4126-C04C-4AE1-B1AC-CDFF0218D537

In case you were wondering, E2DB4126-C04C-4AE1-B1AC-CDFF0218D537 is the UUID of the disk you want to mount. I'm no scripting or CoreStorage pro, but your problem seemed similar to mine, so I hope this can help you. I got all this info from the diskutil man page if you run into any problems.

You will not be able to erase the entire contents of the disk, format/remove the partitions (securely or otherwise) while the volume is mounted. Because of this practical limitation, without having your original installation disc from which to boot into Disk Utility, you're stuck with a system that is in a vulnerable state to sell. While you can create a throw-away admin account from which to securely delete your user profile, OS X still splatters information, such as network connections, all over the place.

As Buscar correctly stated, the resale value on what I would I imagine is a circa 2008/2009 system is low enough already WITH all the original discs. Without them, the possibility of selling is fairly low. The biggest reason for this is that you need the original discs for running diagnostics. Apple Diagnostic software is mated to the particular hardware.

Although Apple no longer supports these systems and, therefore, does not sell replacement DVDs, you can purchase recycled installation DVDs from ifixit.com. I purchased original Leopard install DVDs from iFixit for an Early 2008 MacBook4,1 that was gifted to me without discs. Highly recommended.

With the correct DVDs, you can securely erase the HDD and let go of the system with complete confidence. Alternatively, you may consider simply replacing the HDD in the system with a new one and destroying the one you've been using. Your out-of-pocket cost is probably around the same, but the original DVDs would likely net you a higher resale value.