You will need to create new IMAP account for that. Before that copy all your items to e.g. Local folders and after creation copy them back to the account.
Note: I tried copying my folders and from 200 folders only 2 were copied.
I was planning to copy all in one fell swoop and paste to my global folders, then kill my pop account in lieu of the imap.
Am I copying incorrectly or is there a limit to amount of folders to be copied and pasted at once?
No, there should be no limitation. You can also create new IMAP account, dopy items you want from your POP3 account and then delete POP3 account. Rules won’t be intact basically (you will need only to change folders in them to new ones of IMAP account).
If copy&paste doesn’t work completely, please, describe the process in more detailed way.
I completed 1 by 1 move of the folders to my local folders file tree.
Rules are still in place now that I deleted my POP and remain with IMAP
The rules did not sort on 1st import and I am applying now so hope this sort will work going forward.
I do have an issue though; it seems that new IMAP mail is filtering to the IMAP inbox instead of the Local Folders Inbox.
IMAP account messages will stay in the IMAP account tree folders, Local Folders are for local (e.g. POP3 mail) emails storing. If your rules are not working as supposed, go to menu Tools->Rules, click at a rule and click Modify rule to see whether the Rule preview is OK for you. If not, correct it for right folder/account.