My softshell isn't really stretchy, but it has a bit of give - more than the denim sample, but not enough to really call it stretchy.
I have finished my coat! I will try to take a photo later, but I'm a very bad selfie taker and I find that clothes on hangers always look shapeless. I am very pleased with it. The fabric is lovely to sew, but not on my new sewing machine (the embroidery and sewing machine) which has all sorts of clever features but did not get on with it at all. I bought a pack of microtex needles, as recommended by the fabric seller, and tried the setting for heavy stretch and then heavy woven - no difference at all, both terrible. I was tearing my hair out doing the top stitching with teeny little stitches (even when I changed the stitch length right up to 6mm), missed stitches, odd loops, two broken needles and many, many broken threads. Almost every seam is top stitched.
Eventually I threw my hands up and took it to my old machine. I used the multi-purpose needle that was already in, set the stitch length to 4mm, and didn't change anything else at all. It zoomed around it with perfect stitches as though it was the easiest thing it had ever done.
Because the fabric is squidgy and all the seams are top stitched I don't think there will be any problem with water seepage through them - why is it that the thing you worry about in advance almost always turns out not to be a problem!??