I can't see your second and forth pictures (damn you, school internet, I'm a teacher not a student), but honestly, you might be able to use fabric paint. If you can find a good picture of your character's shirt design, blow it up so it's the size of a piece of printer paper and print it out. Then, put a small bit of fabric paint directly on the printer paper to outline the shapes. After all the shapes have been outlined, the paint should still be wet so press it design-down onto your shirt. Then, remove the paper and you should have a pattern that can be easily finished with fabric paint. So basically, make a stamp? I've never done this before, but have worked with fabric paint and as long as you don't press the paper down too hard, it should work!
Otherwise, if you're okay with not having an exact design, there are other identifying parts of your character's outfit (the belt, skirt, jacket, etc.) so if you can get those near-perfect, you'll have some wiggle room for the shirt and might be able to buy one pre-made.