Fabbing a custom size eink display will cost $200K in tooling + R&D if only they could find a fab that is willing to do sub 100k MOQ orders. Otherwise, it is upwards of $500k. The thing is, no other customer will ever buy a 12x12mm eink display since it is too small to do anything useful, so the eink display manf cannot ammortize the cost of a new line spin up and tooling. It has to be captured and it will be costly.
The entire design with Foxconn / it's customers was specifically for MOQ's of 300k units. We did beta units to 40+ countries.
The NRE for the display was also double your estimate and took around 9+ months to get finished + a few months of delays due to terrible yields on the first Mass produced units.
It would most likely have a single large display, like the Optimus Popularis. Uglier and less convenient, but way the hell cheaper.