My team struggles with similar issues during email and webpage proofing. There doesn't seem to be any way for us to proof emails as they appear to to the user, including live links and gif animations.
The "workaround" we have resorted to using gets the proofing done, but leaves a lot of room for the proof tool to provide better options—We issue a proof in Workfront using a flattened version of what the asset is intended to look like, but then we also have to send a test email or link to test webpage to those same users so they can interact with the actual content our customers will see. The benefit here to using the proofing tool is that it does still allow a single central place for asset feedback and approval.
The downside of course is that you have to both issue a proof and provide a link to the actual asset, thereby doubling the work to be done, AND introducing confusion and a chance for error during the proofing process.
By the way we use Adobe Marketo for email, so it's doubly frustrating that we can't more easily issue proofs of those emails in Adobe Workfront.