Maybe lemon oil would help? Or the sugarcube-rubbed-on-lemon trick?
This recipe would also benefit from a glaze. I think the problem I have with some Serious Eats recipes is that, as is occasionally the case with Cook's Illustrated, they miss the forest for the trees. The sheer delight of producing a vegan scone--and having it remotely resemble a scone--trumps flavor. Complete misfire, in this case.