In the episode 'Road to Germany' (UK season 8/US season 7), there is a cutaway in which Stewie plays with a European See 'n' Say
''8 Simple Rules for Buying My Teenage Daughter''
Play It Again, Brian
Season 3, episode 21: "Family Guy Viewer Mail #1"
Clark Doyle did not have a part on the show Modern Family. However, they did dedicate an episode to him. This is probably what you are referring to.
It is called "Play it again, Brian" and is season 6 episode 10
Perfect Castaway
''8 Simple Rules for Buying My Teenage Daughter''
Stewie doesn't write a book.Brian however, is mentioned writing a book called "Faster Than the Speed of Love" in the episodes "Brian the Bachelor" & "Moving Out (Brian's Song)".Carter gets it published in the episode "420" and it is mentioned once again in the episode "Dog Gone"Stewie does however write a play that becomes a Broadway production in Season 11's "Brian's Play"
Soccer
Play It Again, Brian
Season 8|Episode 16 April in Quahog
The King is Dead
Season 3, episode 21: "Family Guy Viewer Mail #1"
Season 8|Episode 10 Big Man on Hippocampus
Patriot Games
I can't find that line in any episode, are you sure it was a Family Guy episode?
Clark Doyle did not have a part on the show Modern Family. However, they did dedicate an episode to him. This is probably what you are referring to.