How did you come up with the idea that Quan (in Safely Home) would teach and write his book in heaven?
It's on the new earth that we will do earthly things. Unless teaching and writing are evil (part of the curse) or scripture says there will be no teaching or writing on the new earth, then there will be. Human beings who have bodies do things to the glory of God such as eat, drink, talk, think, communicate, rest, work, etc. so there would be writing books, reading books and teaching.
Teaching is the imparting of information. Will there be things in heaven to learn? Scripture indicates there will be learning in heaven (Ephesians 2:7). There will also be books in heaven according to Malachi 4 where the recorded deeds of God's people are on scrolls.
We will continue to be finite beings who live in process: there is time in heaven (there are a number of passages including Rev. 8:1 that indicate this).
So will there be the writing of new books? Why not? Remember, heaven ultimately is the New Earth.
For more information about this book, see Safely Home.