Heya Frink. just a quick suggestion. You might wanna hit a site like Soundbible.com and just look thru their Royalty free sound collection. I bet it would give you alot of ideas.
I did a quick run thru myself. I wanted to add a few more sounds. Like maybe a couple having a argument in another hut or something. But I held off.
Little sounds work so much better when everyone has such a serious face 
Also If you can find a good sound file of a car alarm chirp, I would suggest using that everytime someone lands a ship