Great question John.
Given the situation, the 3–4 week option should the initial focus to stop the bleeding even, if it means more time iterating towards a more viable solution.
- Is there sufficient data on team delivery to state that any given story should work it’s way from ideation to released in X time? If yes, then estimates don’t have much value because there is a consistent reference track record.
- Are the Sr ID, UX-R and Lead Eng on the team, have they worked with the team in the past or are they relative outsiders to the team?
* If it’s 1 or 2 then I wouldn’t spend much time on estimates because the team has shared history and experience, and point #1
* If it’s 3 then I’d ask the team to spend time discussing stories as needed to ensure there’s alignment on how to approach them.