The only places the bonus stories will be available after the Kickstarter is in collected editions of Plume (digital and physical). This is because all three bonus stories (Corrick Origin, Tegan Origin, and New Corrick Short Story) were all Kickstarter stretch goals.
If you'd like to add on the t-shirt or racerback tank top to your reward, just add an additional $26 to your current pledge.
The t-shirt and tank top are listed as a reward on their own at $25 each NOT including shipping. The extra $1 to add it on to any other pledge covers any shipping and handling fees that may arise when your reward is shipped.