On page 4, Tommy taunts the advancing Lectroids by saying they wipe his ass and then go to work at Burger Hut. In this case, Burger Hut is probably meant to be a fictional eating establishment by the author, but there are a number of independent burger restaurants in the U.S. with that name.

On page 6, panel 6, a Lectroid is seen clinging to the ceiling of the bus a la Spider-Man. This may be a use of the small suction-cup-like growths on their fingers, as seen in "Return of the Screw" Part 1.

On page 7, panel 3, Buckaroo seems to have been colored with blond hair in the background.

On page 8, Pecos uses the term "calf rope". This is a slang term for "I surrender", derived from the sport of calf roping.

Also on page 8, Buckaroo refers to the Lectroids as "bugzoids".

Perfect Tommy uses thermite grenades against the Lectroids. Thermite is a metallic powder that can generate an extremely hot burst of heat when combined with a catalyst.

One of the two horses in the trailer being towed by the World Watch One bus is Buttermilk, Buckaroo's horse as seen in "Christmas Corral" (and elsewhere).

On page 12, Colonel John Babyjesus grabs Buckaroo to his chest and says, "Get in my belly!" This is probably a reference to the character of Fat Bastard in the 1999 comedy film of the Austin Powers franchise, The Spy Who Shagged Me, known for eating practically anything in sight and telling his victims to "Get in my belly!"

Colonel Babyjesus is here revealed to be the son of Lord John Whorfin.

Page 14 suggests that Lectroids, once having charged themselves full of electricity, are capable of virtually disintegrating a human being by touch.

On page 16, Colonel Babyjesus, having lost both of his arms in battle with the Cavaliers, proclaims that this is his Golgotha and asks, "My father, why have you forsaken me?!" Golgotha is the site outside of Jerusalem where Jesus Christ is believed to have been crucified. The colonel's query, "My father, why have you forsaken me?!" is symbolic of Jesus' similar one while hanging from the cross, according to the Bible: "My God, my God, why have you forsaken me?"

On page 20, panel 1, the aged Buckaroo clone appears to be playing with action figures of Buckaroo and the Cavaliers, around a model of a Banzai Institute complex.

The clone Penny gives birth to a baby girl from the clone Buckaroo. Buckaroo considers the child his and Penny's daughter, due to the genetic parentage. He names the girl Polly.

The prematurely aging clone Penny dies during childbirth and is buried in a small cemetery behind one of the Banzai complexes. Next to her grave is that of what is presumably the already dead clone Buckaroo. His headstone is labeled:

UNCLE WIGGLY

BELOVED BLUE BLAZER

AKA 'HERB', AGE AND HOMETOWN UNKNOWN

"A FRIEND IN PEACE, AN ALLY IN BATTLE"

The "Uncle Wiggly" reference above is probably to that of the elderly rabbit character of the same name, but slightly different spelling (Wiggily) in a series of children's books by Howard R. Garis from about 1910-1952. I'm not sure where the additional nickname "Herb" comes from. 

Unanswered Questions

Will Buckaroo get a new World Watch One bus to replace the one destroyed here?

What will Polly's last name be? Banzai? Priddy?