So sorry to hear about your dog...Manda!
Manda...I think you should plan on coming down here with the rooms you've currently booked. If Andre still hasn't contacted you by the time you arrive....you can always book a hotel once you're here (low season is in your favor, price-wise). If this still worries you...you know Rob & I will be glad to help you find an affordable hotel...we won't leave you stranded.
Transportation from Montego Bay to Negril will only be approximately $20us...book Clives or Juta for a shared ride...affordable!! You can book this on Friday...if you still haven't heard from Andre.
As far as being alone...that is up to you! There are tourists to hang around with...locals that love to chat (you've already been given advice on how to deal with the more aggressive men

...come to a couple of webcasts...you may be surprised how alone you won't feel!!
Treat this situation like any new adventure....prepare the best you can but always expect the unexpected!! YOU WILL BE FINE!!!