I also tried to make this bikini- but in straight brown, with no design. As a new knitter, I did not check the guage before I started... and it turned out much much much too small. Same with the bottoms.
I ended up making bottoms of my own creation, and found a different pattern for a top online, which I also had to adjust to make larger.
However, mine is knit so fine that I do not need a liner. Sorry, looking back at your original post I realize that I'm not being too helpful. I would suggest washing it on cool and hanging to dry. And, for a liner, I would probably use cotton material.