I think as long as alien stuff becomes just one of the multiple story threads running through this series, and not the main plot, it could be a lot of fun! This series seems to me to be fundamentally be about navigating the asymmetricalities of realationships, and learning to how to deal with people different from yourself. So far, it's gone out of it's way to introduce all sorts of different characters and different relationships, and I think introducing an alien who has known Lulu in a very different context to the rest of the characters, and for a much longer time, fits in pretty well with what the series has established so far.