When I was messing with podcasts (awhile ago) I found this app useful. Its much more than a leveler. Try if for free (at least the the last time I used it). Minimum time/money investment to see if it works for you. I used it online. Never downloaded the app
Use Brusfri app to clean up your audio separately. Better to use the app than apply it on Ferrite as a plugin. Then adjust the Reverb2 under Effects on the guest audio until you’re satisfied with the result.
Let me know if it work with reducing echo through editing. Removing echo is a bit difficult from my experience.
Note: I am not a very experienced audio editor, just someone who does podcasting on Ferrite.