Oh, mint green and white is a great combination--for babies and everyone else, too. Can't wait to see the pic!
I've crocheted lots of baby blankets holding two strands of yarn together. Using sport weight yarn (which is usually the weight I use), it makes a comfortably thick blanket--not too heavy and not too light. Since most knitted "fabric" is not as thick as crocheted "fabric," I bet your knitted blankets are a nice weight also.
I once came across a crochet pattern for a baby blanket that used three or four strands (can't remember which) together for the entire blanket. I never made it because I was afraid baby would be crushed under the weight of all that yarn. Besides, most of the babies I make blankets for don't live in the Arctic!