Cancelled Niece's College Fund Upon Discovering That She's The One Tormenting Us For Months... AITA

My Wife and I struggled with infertility for years, we're still trying more options but we're beginning to lose hope. I have a 16 year old niece that is like a daughter and a friend to me. Considering I'm doing well financially I've decided to take care of her education and start college fund so she could attend a college of her choice.

My brother and his wife (my niece's stepmom) are of course aware of that and they appreciate it very much. They always talk about what a generous, loving uncle I am unlike my younger brother. I've been dealing with a series of unusual, un-explain-able events like receiving texts at work from someone pretending to be my wife informing me of some big news like her being pregnant. Or finding mysterious envelopes in my car when I'm at my parents' and the envelopes contained letters from someone also pretending to be my wife and again telling me she was pregnant. My wife and I had no idea who's been playing us like that. We knew it was someone close and had many that made our suspect list including my BIL.

Last week I was visiting my brother's house and my car was parked in their driveway. I was sitting with my brother and SIL but my niece left for few minutes then returned. I finished my coffee and said goodbye and left. While I was approaching my car I noticed a sign on the windshield. I took a look and the sign read "I'm pregnant" written largely. I was confused because I knew no one from this neighborhood and suspected someone who knew me did it. I called my wife and she again said this was false news. I took the sign and went back to my brothers house to help figure this out. He said someone must've left it on the wrong car but I explained it happened before. He just shrugged but SIL pointed at the sign and said the writing looked similar to my niece's writing style. My brother told her to stop but I called my niece to come downstairs and asked her.

Story 1:
AITA for cancelling my niece's college fund upon discovering what she's been doing to me and my wife for months?
Story 2:
AITA for taking back the money I promised my daughter for her trip after she refused to watch her younger siblings for the evening?
Story 3:
AITA for not forcing my daughter to spend the night at her bio dad's house?
Story 4:
AITA for saying I don't want to do gifts anymore with my family because they come with conditions that I only find out about later?

#AITA #Parenting #Family