I can testify that your assumptions about Bernoulli are not wrong - he is very cool.Whenever I see your pictures I think to myself, “this guy is so cool”.
The material is a flannel, but it was made in Naples, Italy, so it's not a heavyweight flannel - suitable for global warming . The side tabs came with the suit as constructed, along with the button fly, which takes some getting used to.Love, love, love your new suit - the material and pattern are beautiful. Enjoy and wear it in good health.
It's hard to tell from the pic, is it a true winter weight material?
And kudos on the side tabs.