Charlie was right about "bird law". It is illegal in the United States to keep a hummingbird as a pet. The Migratory Bird Treaty Act of 1918 makes it illegal to capture, possess, or kill many species of birds, including hummingbirds, without a permit. (However, he was wrong about bird law with regard to gulls, as gulls are also protected under the Migratory Bird Treaty Act.)
Melanie Lynskey who guest stars as Kate in this episode is probably best known for playing Rose on the CBS comedy Two and a Half Men (2003) and her debut role in Peter Jackson's 1994 film, Heavenly Creatures (1994). She is also the real life ex-wife of actor Jimmi Simpson, who plays Liam McPoyle.
Kaitlin Olson (Sweet Dee) and Melanie Lynskey (Kate) both played roles in Coyote Ugly (2000).
At one point, during an argument with the foreclosed homeowners, Frank picks up an umbrella to use as a weapon. Danny DeVito previously played the Penguin in Tim Burton's Batman Returns, a character who is known to use modified umbrellas as weapons.