So, it's pretty obvious that Matt is going to take out all of the remaining Zapateras and re-enter the game, since the editing is so bad that they turned Mike coming in FIRST into a Matt victory last week.


Anyway, since it's down to Ometepe, I think what is most likely to happen is Grant and Ashley going out before Matt re-enters. Groundwork has been laid for both leaving - Grant eating the Zapatera fish and being an immunity threat; Ashley not telling Rob about Ralph's offer to vote for her in the finals, and her only storyline really being her hating Phillip, AKA Rob's prized goat.
So that leaves a final five of Rob, Phillip, Natalie, Andrea and Matt. I can see Matt going either way - going right back out after he re-enters, or making it to the end as an immunity whore and winning (complete with me vomiting pure venom). Phillip is obviously the F3 goat. Natalie could be this season's "Amber" but I seriously, seriously doubt that because Survivor does not do simultaneously under the radar AND negative winners. So really she's just a cuter, mute version of Phillip as a F3 goat.
I do not think both of Rob and Andrea will be in the finals at this point. Rob's being set up for a fall, and they've also established Phillip/Andrea as possible teammates, with the lingering question of whether or not Phillip will turn on Rob. So, if Andrea makes it to the finals, I think she, Matt and Phillip take out Rob at F5, and then Matt goes at F4. But Rob could just as easily keep his zombies in line and walk to the finals, taking out Matt and Andrea in 4th and 5th.
tl;dr: the person in the finals with Phil and Natalie wins, whether it's Rob, Matt or Andrea.