Here's some info.
1. Fleur De Sel is a type of hand-harvested french sea salt. Sea salts taste different depending on where they come from. Whether you can detect those subtle tastes and whther you like them or not is a matter of personal preference. Fleur De Sel is very expensive. I have a very small container that I use as a finishing salt, mostly on very lightly dressed salads.
I'd suggest she try purchasing very small quantities of different "gourmet" sea salts to see if she enjoys thsm and finds them worth the $$.
Studies have shown that many people, perhaps a majority, cannot tell the difference between expensive sea salt and kosher salt.
2. I have only purchased prepared harissa, but it should be very easy to make, as it's basically just a pepper paste. The only thing is that you'll probably have to use different peppers than they use in tradtional Morroccan or African harissa.
3. Aleppo pepper is a middle eastern spice. You usually buy it ground. It's not that hot and has a deep, toasty taste. I have some at home that I got at Dean and Deluca (distinctive metal can) but I'm gussing that Penzey's or Spice House probably carry it.
You can use it to season many, mostly middle eastern dishes, but can basically be sued like paprika -- though it's pretty $$.
I paint a flatbread with a little olive oil, then sprinkle it with Zaatar
and Aleppo peper and bake them into crackers.