HRHM, what does it matter if the neighbour was invited or whatnot.
Consent is re-negotiated throughout the sex act itself. AT any point during sex, a woman might change her mind because it hurts, or is uncomfortable, or a woman/girl could just think "fuck this, let's stop" and if the man carries on then it becomes rape.
I've had a large number of partners, and I've never been raped because luckily (and I'm aware it's pure luck) all the men I've been with with got this basic stuff.
The difference between sex and rape, I mean.
Actually I despise the word "consent" because it sounds like women are the gatekeepers to men's ucnontrollable urges.
Anyway, my point is that andy "circumstancial" evidence or suppositions surrounding your step-daughter all amount to nothing, because only she knows whether she wanted sex throughout intercourse or not. NObody else except her, and the neighbour knows.
She says she didn't.
Verrrry strange of you not to believe her.