Introduction

My prediction for the final 4 placements and blah blah

4th Place: Baseball

My original idea was Lightbulb being in 4th place, until I thought that the whole reason why Baseball, Suitcase and Knife all teamed up against Test Tube was because she was big of a threat, whilst Lightbulb isn't... Knife and Baseball are both somewhat threats, but I think that Knife will be able to win immunity, making Baseball the obvious choice for them to eliminate.

3rd Place: Lightbulb

Lightbulb isn't as good as Knife at challenges, and I don't think she's going to win because Knife and Suitcase both went through harder situations, so I think the writers will give them a better placement because they deserve it more. Lightbulb winning would feel like they are doing fan-service, but it'd be fun to see what she'd do with the money. 
One thing though, if the final episode is a jury vote, then Lightbulb will get 4th place, as she'll be seen as a threat, this may also happen if there's no voting on episode 15 and it's just a challenge.

2nd Place: Suitcase

I don't have much to say here... she's a good character and a great choice of a winner, but she isn't really that great in challenges and I think that the other one makes a better winner.

1st Place: Knife

Yeah, I'm sure Knife will either get 2nd place or win the season. Knife went through so much development since season one, he grew up, he's self conscious, he is strategic, a great player, he noticed when something was going on with Balloon, but still voted for him because he had to focus on his game, and he also gave advices to people. Even though he calls himself a "jerk", he's way more than that and is in fact, a great person.

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Conclusion:

4th/3rd: Lightbulb and Baseball
2nd/1st: Suitcase and Knife