Reading through the comments already made, a grim picture is painted for you. I agree with what @mikestew wrote. If you do happen to go forward with this then I

Reading through the comments already made, a grim picture is painted for you. I agree with what @mikestew wrote. If you do happen to go forward with this then I would suggest; focus on helping the team ship the product, not changing the process (it seems to be to late in the process to make fundamental changes to mindset). After you've shipped, then you can discuses best practises and whatever in a retro and probably plan a refactor of some sort.