Hi,
If the products have characteristics attached to them, then you need to have one row per variant of the product in the CSV and I don't see that on yours.
For example, for this product on our demo website:
demo.hikashop.com/index.php/fr/hikashop/...with-characteristics
If you export it, you get that CSV:
You can see one row for the main product, and one row for each variant. Do that in the CSV that you're importing and you'll see the characteristic selection dropdown on the product details page of your products.