Well... If you're asking for descripts, I'm the wrong person to ask for given my blind batty eyes.
In fact, I'm the one usually asking for descripts of characters to know what they look like myself.
But if you want explanations of who/what they are, then that I can help you with.
The Army Officer (TMS)
Ruth Buzzi TMS episode. There's a sketch where she's being interrogated by two different Muppets. One of them, voiced by Frank Oz, is Boppity. The other, voiced by Jerry Nelson, is listed in MC's guides as "Spy". However, talking it over with Muppet_dk, we decided that "The Army Officer" was more appropriate given his military secretarial post in the sketch.
Otter (TMS)
Beverly Sills TMS episode. Kermit says that Ms. Sills will be doing an operetta called "Pigolletto". Then, three animals show up backstage demanding that they have an operetta about them performed on the show as well. A cow shows up and asks for Madam "Butter"-fly, a goat shows up and says that they should do "Goaterdamne", and an otter shows up demanding La Trevi-"Otter". Robin then shows up and tells his uncle there's an opera for frogs as well, "Lowen-Green".
The Goat's already listed, and the cow's one of the group already listed, but the Otter wasn't.
Sam Turtle (TMS TV Movie, from EO)
During the special, when Alice and Emmet are talking about the money Emmet's earned from odd jobs, Alice asks about the money Sam Turtle gave Emmet.
Emmet says that they didn't get any money for fixing Sam Turtle's steps, cause the kids were the ones who ruined the steps to begin with. Basically, an offscreen character that's part of the community.
Summer Squall (SS)
The fastest horse in the world. An episode of SS from Season 21-25 shown on Noggin, where Buster gets smitten cause the fastest horse, Summer Squall, has come to SS to spend the day.
Sy, the Pastrami Farmer (SS)
From another Season 21-25 SS episode. This is one of the characters in the magical kingdom of Kanarssee, New Jersey, where we learn of the origins of the Grand High Triangle Lover and how he instituted the Triangle Lovers' Club.
Teenage Monster (SS)
From a Season 30-31 SS episode. This is the one where Telly gets the Super Turbo Teen Power Pogo Stick from his uncle. Teenage Monster is the one who ends up riding the pogo stick perfectly, leading to Telly wanting to ride it even though he's too young.
Tom Wolf (SS)
This is the brother of Virginia Wolf. They showed up at the end of an episode where Big Bird was dressed up as a "Blue" Riding Hood for a visit to his Granny Bird. Unfortunately, he got lost and happened upon the cabin of the wolves' grandmother. Big Bird then introduced Tom and Virginia Wolf as the granny wolf's grandchildren towards the end of the episode.
Obviously, two more for the spoof category.
The Elephant Drummer (TMS TV Movie, from TCT)
The Toy Cars (TMS TV Movie, from TCT)
Wooden Jumping Man (TMS TV Movie, from TCT)
These are all miscellaneous background toys featured in The Christmas Toy.
MuppetDude's the one who helped me get all the main characters and background toys to have a complete cast for this special.
Hope this helps and have a good weekend.