If I understood what you're saying, it seems as though you may have mistaken page title and URL for the same thing. You can alter a page title without affecting the URL and vice versa. For example, in Google SERPs (Search Engine Results Pages), the blue text shown for each result is the page title, while the URL is in green text.
Now, with that said, page titles shouldn't exceed about 150 characters. This is because after this point, the title will be truncated and the entire title will, therefore, not be shown (only part of it will).
Regarding switching the URLs back to their originals, I'd recommend simply changing them back to what they were rather than redirecting them. Either way, it sounds like this whole endeavor has hurt your SEO, and either method may have implications. When you do this, any URL that is not hardcoded should be fixed by WordPress automatically. What this means is, while links populated internally (ex: in menus, navigation, footer) should be changed by WordPress without you having to do anything - though I'd strongly suggest you double-check these manually. However, the hardcoded links (ex: links in body text, images, some widgets) might not be resolved by WordPress automatically. These you will probably need to tend to on your own. Meaning, if in the second paragraph of blog article A, you link to blog article B: you'll probably need to edit the page for blog article A and replace the old URL with the new.
If you need any clarifications or further help, please ask! And sorry if I mistook anything you'd said.