Yelnats, I
have added hangi as a playable word a couple of weeks ago. Of late, I've been tending to answer recent requests, and leave the older ones in the backlog for another day. Also, I try to respond promptly to a new forumite's first request. (To lead them on, you know.)
Creating a Spanish version would depend on having a suitable list of Spanish words - or, in fact, two lists, assuming the aim is to replicate the common/rare distinction. Some of the English language word game apps have very puzzling inclusions and exclusions, and I surmise the developers are not native English speakers. This highlights the perils of building a word game in a language you're not fluent in. And I can assure you that I'm far from fluent in any language other than English.
As for
onager, it's not a word I've come across before, but it is in our word list, along with its variant plural
onagri. For those who don't know, it's either a type of ass or a military catapult. MK is right in recalling a GENERATOR puzzle not long ago, but the mandatory letter was T, so
onager would not have been playable. But there have been other Chi puzzles where the word could have been played. (I can't answer for
The Age. I read it and usually look at the Target puzzle, but of course I haven't been on the look-out for those letters.) The most recent nine-letter Chi puzzle was BOOMERANG last march, with G as the middle letter. In the nature of things, BOOMERANG will come back if you wait long enough.
And there have been other niners and tenners, so keep your eyes peeled, yelnats.