neutron elements works with RB so i am sure the other plugins would do so too.

i got burned buying WAVES plugins which didn't work with RB but i presume these izotope plugins are less 'fussy' and therefore more likely to work with most daws but audacity isn't a daw. it does have a plugin manager but all the plugins seem to be native to audacity and built in, with the only option being enable or disable. at a first glance can't see how you would add a third party plugin.