Many quilters don't line up stripes. Not lining them up actually adds a lot of "life" to a quilt.
As for the triangles, if you starch your fabric before cutting triangles, you will be much less likely to stretch the bias edge out of shape. The heavier the starching, the more stable the fabric.
I think your block is charming. You might want to make 3 more and see how the blocks look together. I'm thinking a narrow sashing might add definition.