Great work, ty!
Haibane Renmei is incontrovertibly among the greatest anime of all time, and I'm glad the art book and some doujinshi have been translated here.
For those complaining of a lack of chapters-there are no more chapters. Abe explains in one of the doujinshi that once the series was picked up by Circle, he would avoid spoiling the series with doujinshi, keeping things mostly lighthearted and ancillary.
The Ganbatte, Rakka! doujinshi linked in the series description is a light-hearted conclusion to the series, detailing the departures of the protagonists we knew, and showing that each new generation has to take up 'parenting' the next, and nobody ever feels ready for it. I think the anime closes things up beautifully but if you have lingering questions that's a good place to look.