I used a DK weight cotton type of yarn for the white and green. This one is an elastic type of yarn it was a mill ends bag from Walmart so I have no idea for sure what it is. For the waist on the shorts I made a drawstring and holes to lace it through when I crocheted around the waist part.
For the top I did a half Double crochet and then did just like you said a double or triple crochet chained one and then double or triple crochet in the next spot after skipping one stitch which is what makes the holes on this one. On the green and white one I just did triple crochets over and over right next to each other so it is not as big of a hole.