It's "The Reptile Room". All the books (except "The End") are alliterations :D

Liam's not Frank's son. It's implied in the Pilot when Frank says Liam "looks a lot like Monica's sponsor." And there's little chance that two Caucasians can have a non-Caucasian child.

This ^.

You're thinking of Cameron Monaghan (Ian). Noel Fisher is Mickey, and he got demoted from regular to guest star, so he probably won't be appearing that much (if at all) in season 6. Which could be a shame, but hopefully, the writers know how to make Ian interesting without Mickey.