MEROKEETY Women's Summer One Shoulder Sleeveless Knot Smocked Midi Dress Split Tiered Flowy Dresses

Can this go in the washer and dryer?

Is there any give/stretch where the top & skirt part meet?

Is the strap adjustable? Can you tie it tighter or make it looser?

What size should I order? the size chart shows even the largest size measurements being smaller than my own measurements Bust-40/waist-34/hips-44