That info should help. One thing to note.. non superwash wool felts. That's the nature of the beast so some felting is to be expected I would think in areas where the baby moves a lot especially as they get older. It's true though that some yarns felt more quickly than others. I have heard that superwash wool is not good for soakers though.
I am very sensitive to wool so I don't have a lot of experience. What some people find soft I still find itchy. Here are some that are the least itchy for me so would probably be considered soft for most people.
Berroco Ultra Alpaca (the fuzzies in alpaca can be itchy for some people)
I also found this link comparing soaker yarns