I started with white shirts from the thrift store. This is why the shirts are so different from each other. They are also not ideal for a pattern (turtleneck and a pocket), but that's what I found, and they cost me a grand total of $1.30. So...two white shirts.
Next, I found some pumpkin clip art, which I enlarged for the baby shirt and enlarged some more for the toddler shirt. I transferred the outline to fusible web...
...which I attached to orange polka dot fabric. I also drew some stems freehand and cut those from some brown polka dot fabric.
So here are all my pieces, including some extra-large green rickrack for the vines. (Hannah got a real kick when she learned we were buying something called "rickrack." That was funny enough to keep her entertained while we were waiting at the cutting counter.)
I fused the fabric to the shirts, then stitched over the edges. In retrospect, there should have been some stabilizer under these, but good enough is good enough.