Help me choose a wool (blend?) for baby blanket

I’m crocheting a stroller (blanket with arms) for my granddaughter. I want to use a yarn with a high proportion of wool that is also washable. I’ve spent way too long thinking about this and need some help.

Here’s the criteria:

1 soft and not itchy

2 As much wool as possible but a blend is ok especially if it has other natural fibres

3 washable without too much pilling or stretching

4 nice rustic neutral colours— bonus if there’s heathers

5 easily available in Canada

I love cascade 128 but it’s too thick. I probably need a dk or worsted.

Cascade 220 sw has the colours I like but is it soft enough? Will it also stretch out of shape?

I have used drops bay merino and it stretched way way too much. I have also considered berroco ultra wool or Estelle merino. Also thinking about a sock yarn with nylon or berroco vintage.

What do you think?