Mark,
I found that the digi and the lcd work independent of one another. There is nothing to worry about the"buffer" between the two. In my case, the first digi I got the ribbon/glass connection point started peeling up and I got intermittant operation. (Luckily I didn't stick everything together yet). With my second digi I got, intermittant operation again. Eventually found that the connector, both digi and lcd were finicky. I used the sticky and the existing foam rubber to help keep these connectors in place. Everything good now.