As specifid in REST spec: https://github.com/ezsystems/ezpublish-kernel/blob/master/doc/specifications/rest/REST-API-V2.rst#xml-example-14
Limited to sectionFacet, userFacet, contentTypeFacet. And as stated in the Solr fix, currently limited to name, minCount and limit. Criteria/filter and global flag is not, so filtering on facet is currently something that needs to be done in a custom way by user until M2 on Faceting is done.
However we are lacking examples of all three cases, it's too difficult for anyone to reverse engineer this from the xsd.
Best would be to get Sławomir Uchto to help expand doc on REST to have examples of us, alternatively we'll need to postpone that to Facet M2 when a more full example can be made.