Hi Mark.
I just caught up on this thread and see I got a mention!
I'd say your on the right track with your process but, FWIW, I didn't use sanding sealer on mine.
I did ebony timbermate, followed by water based dye, followed by wipe-on poly.
Simon makes a good point about the oil based sanding sealer with water based stain/dye. Not sure if there'd be compatibility issues or not. Worth testing as per SB.
edit:
Shame about the faux rosewood board. I would have talked to Adam and swapped it myself, but you're truly past the point of no return now!