I share your theory of why she committed suicide.
I also agree that IF Rebbecca committed suicide, that is the most likely scenario. I remember reading a post WAY back near the beginning of this thing about her ex-husband saying in an interview that she had decided she wanted a life of luxury.
So, MS is severly injured in the house while you were there, and your boyfriend calls and tells you he holds you responsible and to get out. I'm not saying that she was selfish or greedy, she seems by all accounts to have been very nice. But to have all that happen, and then get kicked out of your beautiful new life by the man you love, be blamed by him for his son's death, it could have been the straw that broke the camel's back.
If she killed herself, though, like Babette suggests, I believe there was an element of lashing out at JS.
There would be no other reason for her to tie her own feet up as well as her hands behind her. The hands being bound behind you are to stop yourself from freeing yourself. But the feet? Almost impossible to do with the bound hands, and for what, if your intention is just to kill yourself?
That gossipy article we read that has been repeated over and over, that is trying to say that the police believe it is suicide, the only case of suicide it mentioned where the hands
and feet were bound was when a man was trying to make his suicide look like murder so his family could get his life insurance payout. There would have been no payout for suicide.
So, in my opinion, Rebecca was murdered and it was staged to look like a suicide, or she did committ suicide, but tried to make it look like JS murdered her.
God help me for thinking up such things!