tintin - "stepwise" means that Y appears in the grid in a series of descending steps. Can't help with the "homophonically" yet (although I think I know what I'm looking for......half a dozen yet to complete).
kirky - you'll know if you have Y - a quick Google of the 'nom de plume' should confirm if you're unsure.
xwordfan - if you've got 6 of the 7, I'd assume that the 'nom de plume' should be fairly familiar.