I'm sorry to hear about your housefire man. Hopefully I can help you out a bit. I recently cloned all the XC3P boards complete with full BOMs for each board aside from the XLCD. For replacement parts or if you just want to make new boards from scratch you can checkout the github repo here:
https://github.com/Element18592/Xecuter-X3CP-Boards
As for the white diffuser you can rob that and the LCD itself from another HD44780 LCD to rebuild your XLCD.
The connector on the Xenium itself is SM02B-SRSS-TB. These are two mating cables with different lengths. Buy whichever one you need and cut the connector off of one end.
6" cable: https://www.digikey.com/en/products/detail/jst-sales-america-inc/A02SR02SR30K152A/6009377
12" cable: https://www.digikey.com/en/products/detail/jst-sales-america-inc/A02SR02SR30K305B/6009393