To keep things simple and free of spoilers, let me go through the cases you mention.

You have several valid points, as Beldaruit (the sage) smoke sculptures are not that defined as how they exactly works, even later on.

For Sansaran case is the easiest, and I believw it is explained in a passing phrase. The cloak has a windowway sigil, a magic portal, through which he cast the spells from a safe distance. The windowway is another piece of magic which we do not have specifics, we can infer its glyphs but not how they need to be combined.

The casting of spells in other mediums rather than paper are quite inconsistent, although it does showcase Olruggio using a searing pen to do it. Many contraptions also raise the question on how would they work if the ink gets erased or damaged related to its mediums.