Visible crew/equipment: When Topanga carries Cory into the room you can see a crew member's hand triggering the doors to open.
She's Having My Baby Back Ribs - S7-E17
Continuity mistake: At the start, in Cory and Topanga's dorm room, Topanga asks if Cory thinks she is attractive. He says "Of course I do. Come here, I'll prove it" and leans on his side and tilted back. When the shot changes after Topanga starts walking towards the closet, he is suddenly sitting upright. (00:03:29)
How Cory and Topanga Got Their Groove Back - S7-E18
Continuity mistake: Cory is walking around taking back flyers he'd earlier passed out. In one shot he grabs a flyer out of a young man's hand but in the very next shot, the young man is still holding the flyer. (00:08:57)
Continuity mistake: When Cory is "The Coconut Guy" he is showing Jay Leno, David Letterman and Arnold Schwarzenegger. When Topanga comes to the shop Cory knocks the Arnold Schwarzenegger coconut down but in the next shot, it is perfectly straight up. (00:12:04)
Continuity mistake: After Eric pulls the doll from out of the grill, he closes the lid. The lid then alternates between being open and closed throughout the rest of the scene. (00:03:44 - 00:06:15)
I'm Gonna Be Like You, Dad - S7-E14
Continuity mistake: When Topanga, Shawn and Angela are hanging out in Cory and Topanga's dorm anticipating Cory's return from the doctor, the slice of pizza that Angela is eating goes from having a small bite taken out of it, to being halfway gone, and back to having one bite taken out of it. (00:12:07 - 00:14:02)
The War (1) - S7-E15
Continuity mistake: After Rachel sprays water all over Cory, the amount of wetness on his shirt varies throughout the scene. (00:05:53 - 00:09:05)
Continuity mistake: When Eric is hugging Angela, her arm is on his shoulder. In the next shot, when Jack is saying "How am I going to survive without money?" you can see, between him and Rachel, that Angela now has her arm on Eric's back. (00:16:58)
Continuity mistake: When Topanga is telling Cory that she had her internship interviews in the morning, her arms are folded. When the shot changes, her arms are down at her sides. (00:07:39)
She's Having My Baby Back Ribs - S7-E17
Continuity mistake: When Alan remarks that Amy never got her figure back after she gave birth to Eric, her arms are folded. When the shot changes, her arms are down at her sides. (00:10:10)
Continuity mistake: When Cory enters the noir world and uncovers Topanga's corpse, you can see her left hand is draped over her stomach. After the noir version of Cory confesses to the murder, the cloth covering her body is now suddenly covering more of her torso, including the left hand. (00:17:53 - 00:19:15)
Continuity mistake: When the noir version of Shawn is asking Topanga what she's running from, the pot of coffee is next to his left arm near the edge of his side of the bar, and the coffee mug is slightly to the left of the crease in the bartop. When the shot changes after she asks him what he means, the mug is now directly over the crease, and the pot is in the center of the bar between the two of them. (00:06:53)
Continuity mistake: When Morgan is telling Topanga that she wouldn't use her bridesmaid's dress to wipe her ass, she gets cut off by Alan who covers her mouth with his left hand and then begins dragging her out of the reception hall. When the shot changes, he is covering her mouth with his right hand. (00:17:22)
Continuity mistake: When Cory is saying to Shawn "Are you going to nice yourself out of the girl you love?", Shawn's right foot is resting on his left knee, and his left hand is on the foot. When the shot changes, his left foot is now resting on his right knee, and his left hand is resting on his left thigh. (00:05:06)
Continuity mistake: When Shawn stands up on the chair to propose a toast, Eric is at his 9 o'clock. When shot changes, Shawn has instantly rotated his body so that Eric is now at his 6 o'clock. (00:16:47)
She's Having My Baby Back Ribs - S7-E17
Continuity mistake: After Cory says "You don't have to tell me that" after Shawn compliments his waffles, Shawn is shown holding the fork pointed down towards the waffles. When the shot changes, he is suddenly holding holding the fork perpendicular to his body. (00:04:35)
She's Having My Baby Back Ribs - S7-E17
Continuity mistake: When Cory gets off the bed he leans against the dresser and his hands are behind him. When Topanga walks in the room, his hands are by his sides. (00:03:50)
Continuity mistake: When the voice on the intercom is saying "Paging Dr. Chocolate Pudding," Cory's right hand is on Topanga's right arm, and her hands are in her lap. When the shot changes, both of his hands are suddenly resting on his stomach, and her right hand is suddenly resting on his left leg. (00:07:23)
Continuity mistake: After Topanga and Angela hug, Angela puts her hands on Topanga's arms. When the shot changes, Angela's arms are suddenly down at her sides. (00:18:27)
How Cory and Topanga Got Their Groove Back - S7-E18
Continuity mistake: When Eric is saying to Jack "It was you all along," he points his left-hand index finger at Jack, who is shown writing down the lottery numbers Eric provided him. When the shot changes, Eric is now pointing with his right hand, and Jack's hands are suddenly on his hips. (00:16:40)
Answer: Topanga's middle name is never specified. Considering her sister's name is Nebula Stop-the-war Lawrence, Topanga's is probably something equally unusual.