I use redactor daily in a piece of software. It's awful. I can't add a list to the input without it making the entire contents of the editor into a list item. Then after the list, typing becomes invisible, requiring a page-save and then re-edit.
So you're agreeing that it isn't out of date then, since IPS4 hasn't been released. Tracker will be updated, although it isn't high on my list of priorities. Hopefully a few other developers are going to help out with it too
Your conversion sounds quite unique due to the add-ons you are using.
In my opinion, to keep all of your extras (including the same IDs for topics) you are going to need a customised conversion. A 3rd party developer could do this for you, or you could email email@example.com to see if they can help out.