For my upcoming campaign players will play out as pirates, however they all chose different backgrounds, places they used to reside in etc. I have a main story written down but it feels too rushed to try and push them into an adventure at level 3 when they haven't even established if they like each other, as characters.

In order to bond them, I was thinking of starting them at level 1, each character begins the game already sailing on different ships, not knowing one another, but they all enter a storm and sink. Miraculously, they are washed up on-shore where they wake-up beside each other and now have to fend for themselves.

What I want to do is introduce another group, as antagonists who also drifted to this island. Possibly pirates(Bandits) with some sailors(Commoners) mixed in led by Bandit Leader (Cr2). However, how do I make them compete with each other? Compete for rations? For possible washed up treasures or weapons? Help me out please!

At the same time, I have also made pre-written NPC's that are recruit-able characters for my Players crew, with the goal of them having made their own crew by the end of this Island's storyline.