Ooo... Tough choices. The only one I don't really like is Option 3, but even that's good for a survival game. You have to adapt work with what little resources you have including the people around you. I'm assuming creating the characters would allow for the player to choose specialties or classes. that'd be cool for the high customization.

Personally, I like the starting solo and seeking out allies. The only issue of that it's different enough form the others that it may change alter the style of game a bit. There's a couple benefits, too. One: There can be more people to find than your max party size thus giving the player a choice of who to and not to add. Two: You may have to rescue some or all of these characters and failing horribly may force you to go the entire game solo. (Or intentionally failing to make it challenging )

The other three options are all pretty common in these types of games so the gameplay will remain the same regardless of what you pick. my first choice is option 4

If that strays too far off of the type of game you're trying to make I vote Option 3. Who doesn't like lots of customization choices?

You could also have difficulty setting use a couple. Normal mode allows you to customize your party. Hard mode forces you to work with randomly assigned characters.

You're actually hitting on a few ideas I intend on using.

I'm assuming creating the characters would allow for the player to choose specialties or classes. that'd be cool for the high customization.

 

 Two: You may have to rescue some or all of these characters and failing horribly may force you to go the entire game solo. (Or intentionally failing to make it challenging )

Is there any reason you don't like option 3 in particular?

Survival games are all about working with what little you have. I feel that restricting the player a bit fits the theme better than giving them a ton of customization options. Still, people tend to like customization so I think the three options will have about the same appeal to the audience.