Yes - there will be a pledge manager for adding or changing items later.
Since the campaign is for Fugitive, the add-ons are not available for the $1 tier. If you just want those items, you can purchase items those separately here: http://fowers-games.myshopify.com/
They will ship in November with Fugitive. They are discounted because it's cheaper to ship them together.
Don't see the answer to your question? Ask the project creator directly.