So I have recently gotten a few ads for Merge Mansion and remembered that MatPat made a few theories about it a few years ago. The ad I can't physically show for reasons of the fact that I can't save the ad as a video, but I will explain it the best I can. In the ad, it shows a younger Granny Ursula driving and coming across a car on fire. It cuts to a child in the burning car with a doll in the seat next to the door. Ursula opens the door and gets the child out, and the ad shows that Ursula was a brunette interestingly, and then cuts to Granny Ursula hugging Maddie, which shows that Maddie was the child in the burning car. I cant remember if this part is the same ad, but it does show Ursula and Maddie looking at a grave that says "Michael and Becky Boulton." My guess is that these two are Maddie's parents who died in the burning car.
Another one shows a familiar scene. Maddie fixing up the house and Granny watching. Maddie finds a door behind the wallpaper, and I point out the fact that Granny looks surprised about the door. I don't remember the ad exactly, but if I remember correctly, the ad stopped after the door opens. This ad shows what was behind that door. Maddie goes into the room and finds a crib halfway covered by a blanket, a doll on the floor, and the room has clearly never had anything done with in a long time. My guess is that after Ursula found Maddie in the burning car, she threw the doll into the room and sealed it up. Maddie picks up the doll and remembers the burning car and someone reaching into the car to get her out, and this ad ends there.
I'm lumping all of these together, mostly because I've only found them once or twice, so I don't remember much about them. One shows a woman that Ursula clearly knows, and it seems like the woman wants to break down the old mansion to build a hotel. She seems younger than Ursula with her hair only having a few strands of gray hair, with the rest of it being a grayish-black. Ursula clearly wants to make the woman think that she's gotten what she wants by Ursula going to prison. Another shows a train wreck and Arthur cheating on Maddie when he was supposed to be on the train that crashed. He looks at the woman he's cheating with, I also point out that this woman, that Arthur is cheating on Maddie with, and the woman who wants to wreck the mansion are not the same women. The ad continues with Arthur arriving at the mansion from a taxi and looks covered in bruises. Maddie runs over and hugs him, clearly very happy that he's okay, but Granny doesn't buy the bruises. She rubs her finger over one bruise over his cheek and reveals that it's makeup. Maddie dumps him after this, and some of the ad is Arthur trying to win Maddie back, and failing. The ad ends with a file being slid under Arthur's door and him looking through it. My personal theory is who slid the file under Arthur's door is the woman who wants to replace the mansion with a hotel.
That's all of the ads that I can remember at this point. If anyone wants to add anything, then feel free to.
Edit: I almost forgot! They also have a YouTube channel. It doesn't get uploaded all that often, and mostly gets updated with videos about the updates for the game, but it does exist! https://www.youtube.com/@MergeMansion/videos is the link for the channel.
Edit #2: So I just got another one, and Imma explain it real quick before I forget about it. The ad starts with Arthur putting hot sauce in his eyes, and going over to Maddie, who is upset about something that we don't see. It cuts to the wedding scene with Arthur nearly putting a ring on Maddie's finger. Ursula busts down the door with pictures, and we see the black haired woman in one of the seats. She trips Ursula and the pictures fall out of her hand. The pictures show that Arthur WAS cheating with the black haired woman. This man is the absolute worst imo. My theory is that he was only with Maddie to get close to her and to try to convince her to agree to breaking down the old family mansion.