After exchanging a few emails with JLC and getting nowhere, I actually tried ordering the board. The BOM left the JLC Assembly box blank, so I had some doubts.
I uploaded the Gerbers, BOM and P&P files, and the quote page shows the LEDs will be installed, and the price of them is listed on the quote. So apparently, this is an issue with the EasyEDA BOM. It will be a while before I order the boards, but it looks like the WS2812 variants from the assembly library should be ok. Just make sure they show up properly on the quote page and on the board image in the quote.