We have United booked out of EWR to SXM for November. No back up plan, never got screwed by United (YET!), hopefully they won’t have as many problems in November as not as many people will be traveling as in a summer and no thunderstorms.
Sorry to hear about your messed up plans to Europe. We are flying British Airways in ten days, hopefully it will go smooth. At least the flight won’t be canceled, might be delayed but not canceled as aircraft will be already here from Heathrow and they usually don’t cancel out of there.