To my knowledge, no, she wasn't ever announced as being the main focus.
Luxee's previous game was very linear, and the main reason this game exists is because they wanted to try something different, hence the more open, sandboxey style.
That also means that they aren't forced into a linear timeline for development.
While we have no way to have a concrete answer here (bigoted shitheads on this site effectively caused Luxee to give up on this place entirely and stop interacting here), it's fairly safe to assume that they mostly work on content depending on inspiration, since the nature of A69 allows for it. This means that Nea has, so far, more content because Luxee had a lot of ideas and inspiration for her. It's pretty obvious that they like trans feminine characters, so it's unsurprising.
But given what the next update is shaping up to be, it's also fairly safe to consider that the others will have more content as well, as Luxee gets inspired.
While it can suck for people who have no interest (or the visceral hatred some of the more stupid here have shown...) for Nea, it also, in my opinion, seems to work out well for Luxee. Not all creative people work the same, and as someone who function the same way at it seems Luxee does, focusing on inspiration and ideas tend to lead people like that to a lot higher quality and a lot more motivation.
Now, if people would stop harassing and insulting Luxee, that motivation wouldn't get trashed all the time, but what do you know, a lot of the people who get smut games for free tend to be assholes, so...