Quicksilver lancers is a [1] option added to Stormwind Cavalry in the Elf Master List (CoK22)
Sylvan Kin get Stormwind as an Irregular unit (UE) with an additional option of Pathfinder (CoK22)
The only options (unless otherwise stated) which change between Master and Theme lists are the army wide special rules - you cannot taken them unless both M & T have the same one [so SK characters can’t take hunting cats, but Rhordia human units can get Indomitable Will for example].
The fact that Quicksilver lancers option isn’t shown on the SK page doesn’t mean they don’t get it prior to BRB.
If the SK Stormwind entry is separate from the main elf one then it will only have options lists
Just noticed that the Sylvan Kin background is not in the free background PDF on the Mantic homepage. Ist that a mistake or on purpose? Does it get eworked together with TK?
also seems weird to forget an entire name for a special character haha, these things happen when publishing things. it might get fixed, or the Sylvan Kin might get Fancier. I’m guessing the former!
The SK Stormwind entry, completely separate from the Elf one, appears to me to be fine, balanced & free-standing - ie the Lancers aren’t available and instead SK get pathfinder