Snitches - drop out of school, make it alone, waitress, choose to inform on the gang ... and then have that go wrong. I've not dug deeply into how that happens. The one time I informed, I got the "swingers" ending instead.
Pregnant Prostitute - there isn't one called this; do you mean "purple prison prostitute"?
Note that as
icewanted said, most of the new endings seem to require dropping out of school. e.g. many come off the prison route, while cuckqueen is triggered if you are barry's pet when you flunk out, etc.