Only Murders in the Building Headcanon - Theo and Teddy Saw a Musical Together
This is going to be really niche, but after seeing Theo and Teddy again in 5x02, I had to share this.
One of the things we know caused Teddy and Theo to be somewhat distant is that Teddy couldn't share his love of music and theater with Theo so easily due to his deafness.
But in 2003, there was a Broadway revival of the musical Big River co-produced with Deaf West Theater in LA, that featured deaf and hearing actors working together, including in the lead role of Huck Finn.
If Theo is about the same age as Mabel, he'd be an older kid/preteen when that came out. So, I can't help but think Teddy MUST have taken that opportunity.
Can you imagine how exciting that would have been for Teddy? How nice it might have been for little Theo, who was probably dragged along to a lot of his father's plays, to finally understand what was going on for once?
Oh, and bonus: Here's Nathan Lane presenting a performance from Big River in 2003:
(And yes, before you comment, I know about the Deaf West Spring Awakening production. But this came first, and I don't see Spring Awakening as a father-son viewing experience. Maybe Theo went and saw that himself...)