The fabric you’ve posted about looks like it has a stabilising thread running through it, so it may not be as stretchy as you think and behave more like a stable, but loose weave. I would get a sample and see what it’s like.
I haven’t sewn this type of fabric yet, I have some similar in my stash, but I would sew the seams with 4 thread overlocker and stabilise the shoulders, and use a knit interfacing. Hopefully, someone will have sewn this and be of more help.