The one to watch is Iluka who received a AUD 1.65b loan from the Australian Government to build the Eneabba rare earth plant, currently to come online in 2027. Their stockpile is xenotime and monazite and Yytrium and Erbium are a priority for processing.

https://www.iluka.com/products-markets/rare-earth-products/

Not sure about Lynas and whether they have access to those rare earths from an alternate source to feed into their plant. The Mt Weld mine is carbonatite and mostly LRE rather than the Yytrium and Erbium heavy xenotime/monazite Iluka have stockpiled.