For some reasons, the Outreach Wiki should also be a Wikidata client wiki, so e.g. the outreach Education program can be linked together with its Meta-Wiki corresponding page and probably statistics datas can be synced from properties values.
|Open||None||T109579 [Epic] Give more sister projects access to Wikidata|
|Open||None||T171140 Enable Wikidata support for Outreach Wiki|
This is the last big project that doesn't have support other than Incubator (which is on the roadmap) and maybe Wikitech. Anything else is very arcane and would probably not benefit much from Wikidata access.