Is it possible (recommended) to replace Iceweasel with Tor Browser? I like using Tails a lot, but I need my browser fingerprint to match that of TBB. Is there anyway I can replace Iceweasel with TB and still be able to use Tails?

Is it possible (recommended) to replace Iceweasel with Tor Browser? I like using Tails a lot, but I need my browser fingerprint to match that of TBB. Is there anyway I can replace Iceweasel with TB and still be able to use Tails?
Isn't the Tor Browser identical to Iceweasel?
It's not. The Useragent is identical, IIRC, but there are minor (or maybe not so minor) differences that allow an adversary to tell the difference between the Tor Browser and Iceweasel.
Does this mean the fingerprints are identical? I thought this way technically unfeasable.
The short answer would be "no".
But there's no such thing as the fingerprint of a web browser, be it TorBrowser or Tails' current web browser. The closer you look, the more identifying bits you get, and the smaller the anonity sets.
So, at some scale, the answer is "yes", and at some other scales, the answer is "no". Next thing to do: ?evaluate web fingerprint.