In account settings there is a "local Directory that can be used on a per account basis to specify a location for "that account" to store data. Clearly this is what has been used to specify a storage location for these other accounts.. It can be used again for this account, but it is far from the ideal method as it makes migrating the profile a process requiring all the parts be copied and on the new device all the paths to all the parts be the same as before. Given windows penchant for renaming drive letters when devices are plugged in I am sure you will understand it is a disaster in waiting.

If bandwidth is not an issue, I would recommend actually removing the three existing accounts (or all four) and moving the Thunderbird profile to the remote location rather than having bits of it all over. Then re adding the accounts to refresh the data.

http://kb.mozillazine.org/Moving_your_profile_folder_-_Thunderbird

By moving the profile folder, you will free more space on C:, put all of the Thunderbird data together for backup. (I bet if there is a backup it backs up C: not E: so none of the mail is actually backed up.). It will also make migration of the profile to new hardware as simple as copying the profile.

The 3wo2547u.default should not be identical. Thunderbird will use one for the active profile. the other will have files dating from when the data was copied.

You might also want to look at the need to store mail locally at all. These are IMAP accounts, so if the store mail locally for offline use option was deselected the mail would still be available but on the whole (some recently viewed mail would still be in the local cache, different to the imapmail folders.) the message body would be downloaded from the server as needed, rather than having a mirrored copy locally which is not immutable and may disappear at any time the mail is removed from the server.

If drive space is an issue, why the mail is being fully downloaded must be explored.

Thank you Matt, The accounts listed are for example, there are more accounts, some are pop accounts etc..

In reference to "In account settings there is a "local Directory that can be used on a per account basis to specify a location for "that account" to store data. " In order to consolidate, wherever the profile ends up, is it just a matter of moving the folder and then update the account settings to the new location? Or is there more to it?

Not sure why my post is showing up odd looking, but hope you can read it.

Your post showed up as it did because you put spaces at the start of the line. Handy to cores a fix width font. A pain if folks listened when they were at school and start paragraphs indented

You are correct about moving the folders, but most folks these days actually struggle with anything in the file manager. This is compounded by the fact everything has to be done in offline mode. Otherwise you wil be copying files when they are being updated or copying files and on restart new ones are created for the new mail