I finished my 4 samples, and if you're curious to see, here's the comparisons of the 4 cast ons and bind offs side by side
I was surprised at how well long-tail cast on and traditional bind-off held their own.
I've heard twisted German cast-on described as one of the most elastic, but if I've performed it right here, I didn't find it particularly so. It's stretchy, yes, but I didn't find it a match for tubular cast on as far as returning to its original shape.
The alternating cable cast-on seemded to be middle of the road with elasticity, and I like the look of it.
As far as bind-offs, I didn't see much competition for kitchener stitch bind of as far as elasticity. Traditional bind off in pattern seemed next best to me, although significantly trailing. EZ sewn bind off and Russian bind off both seem less elastic, but with the EZ having the edge. Appearance-wise, I thought the Kitchener stitch bind off was most attractive, followed by the Russian bind-off in pattern.
Those are just my impression though, and some of these I was trying for the first time.