
Well the chocolates easy if you know how to ferment it, then I think you roast it and it turns into a paste. And the hair products there's a lot of ways, it just depends on your hair type and how you make it, like clay can add moisture but other types strips and dries it out. Shea butter and coconut oil is good and during this time period soap/cochi nuts and different flower oils make really good shampoo they're pretty abundant in the fantasy realm

i'm not that ambitious but there are people out there who are supermen and superwomen who seem to have 5 lives mushed in one. Need to have good project management, delegation, efficiency, an excellent working force and an excellent network. For sure that's not all there is but these seem to be some key things that Iris has nailed down plus her past life knowledge and wisdom. She was handed an opportunity in this new world and made a lot out of it; with more to come I'm sure. And she's more humble than the arrogant male equivalents that there are so much of.

For the chocolate, she only discovered the ingredient in the world. But she left it to the chef to whip up their version of chocolate. Plus, anyone with the internet could have searched up how chocolates are made on the internet (I have cos i was bored), and just relay the steps to the workers who have had experience with fermenting and all that stuff. They probably did trial and error as well to produce their own version of it. Plus, the designing of the dress, she just sketched out what she wanted and ordered the designers to replicate it.
I wouldnt jump the gun that she's a mary sue. she just hustles well

Sometimes you're just curious about things. I also create my own hair products, cosmetics and other things. I like to cook and I know how to make cacao powder to add to drinks, cacao nibs, vanilla extract, pasta, flours, cheese and other things. I also know how to dye clothes with plants, repair basic electrodomestics, give first aid (and take blood pressure, inject), and so on. It just depends on what you are interested in and what you need.
I am a teacher, so I do these on my free time (usually on weekends) and I do it because I think it's much cheaper than buying.
We are in an era we can learn a lot just searching on Internet ;)
iris is such a mary sue?? how does she manage to do all of these things she can make hair products design stuff manage her company etc like i get its supposed to be unrealistic but this is too much not to mention everyone who meets her loves her basically