The house was not as large as you see in the picture at the time. Construction in 1843 enlarged it to 17 or more rooms. What the number was before then I don't know. What is known is that after she moved out of the house she continued to teach the Smith children for at least another month.
In regards to Emma, Eliza later wrote in her journal:
I once dearly loved ‘Sister Emma,’ and now, for me to believe that she, a once honoured woman, should have sunk so low, even in her own estimation, as to deny what she knew to be true, seems a palpable absurdity. If . . . [this] was really her testimony she died with a libel on her lips—a libel against her husband—against his wives—against the truth, and a libel against God; and in publishing that libel, her son has fastened a stigma on the character of his mother, that can never be erased. . . . So far as Sister Emma personally is concerned, I would gladly have been silent and let her memory rest in peace, had not her misguided son, through a sinister policy, branded her name with gross wickedness.
If the stairs story was true, Eliza had ample opportunity to confirm it and any miscarriage she may have had. Elizas only anger toward Emma was the denial of plural marriage, a situation known by many to have been problematic for Emma. Our own section 132 of the Doctrine and Covenants being a letter directed toward Emma.
The stairs story is false, and Eliza loved Emma by all accounts. I do not think this would have been the case if an assault and subsequent miscarriage had occured.