This garment is my very best friend for summer evenings spent out of doors. It’s very lightweight and folds to fit in your purse.
I used less than half the ball of Noro Taiyo Lace and a bit more than half the skein of Pima Lino. I haven’t tried to get two ponchos out of the single balls called for, but I get the feeling there is enough yarn to do so. Maybe do the ruffle in Taiyo?
Substituting yarn can work, you go heavier and warmer. Do a swatch and cast on one pattern repeat’s worth of stitches less.

The needles you choose can be flat or straight for the two rectangular pieces, but must be circular for the ruffle, a 24 or 36” cord will be fine.