My fabric is a knit too and I'm using minimal structure/interfacing. It's an experiment, I am inclined to add more but want to see whether it will work to create a jacket that will feel more like a cardigan, without being the famous Chanel style.
This is what I have done:
stay tape in shoulder and neckline
I did not interface the front or make a shoulder stay. While working on it I'll decide where to add more (probably the hem at least).
Thank you all for the nice comments on my coat. Loved to read them all.