Argh, I had that second link to GH pima cotton PJs wrong. Use this instead. They're as close to mama Hannas as you can get, and prettier (gasp) but not cheaper: https://www.garnethill.com/asian-wra...leepwear/17160
I have some Hanna mama sets in S if you are interested - that I bought but found too warm!
ETA Have you tried plain old Gilligan and O'Malley at Target? In the past I have bought sets in 100% cotton (at least the pants).