BBMHow is this theory more simple than any other? It has more non-verified hypotheses in it than most, IMO. You have no evidence that she had any kind of relationship with AA except texting from 6 pm the day before she died and him having her Tinder photos and other downloaded pictures on his phone.
You don't know that she had a boyfriend, much less 2. She may or may not have had 2 SD's (and the whole point of them is to limit the time you spend in return for an allowance - and to enjoy the limited time you spend with them).
Too many maybe's. What you just wrote out is far from simple.
The last I heard, he had photographs of her, including her profile photograph, on his phone. Is there some source that says they were from
Tinder?