The bare LCD screens and 4mm dome contacts arrived from Aliexpress.  The LCD screens are right size and match the footprint for the alpha board.  They are thinner than the stock screen so mounting with some foam adhesive looks like the best route for installation.

I stuck a few of the dome switches on the alpha board to test things out.  They give a nice solid click but the fiddly-ness of installing these has been confirmed.  When the case is fully snapped shut, some of the buttons stopped working.  I thought it was an alignment issue at first but looks like the alpha PCB is twice as thick as the stock PCB (1.6mm vs 0.8mm).

Still haven't soldered up a test board yet.  I just added a diode laser cutter to the work shop and was hoping to get it setup to cut stencils from mylar.  This became a project in itself clearing a spot in the workshop, building a stand and enclosure, and running ventilation.  Cutting the stencils out is still a work in progress.