Set; assume a spearman (feature "set") is facing an opponent (say using a longsword and who wins initiative), I would allow the spearmen to attack first when the longsword wielder moves into attack due to the weapons range and then the longsword wielder attacks second in the first round before reverting to longsword attack first then spear wielder second in subsequent rounds (i.e. following the initiative results)
Sneak (this could be removed as its the same as "auto" so thanks for the catch); assume a roguish character wants to use a garrotte to choke an opponent. From a mechanics standpoint I may require an agility check outside of combat to get into position and then ask the rogue to make an attack (a combat manoeuvre). On a success I may allow the rogue to assume a choking position which then automatically causes damage each round unless the opponent can break free as their action (could use agility, strength, melee combat or even athletics opposed skill checks depending upon how the player and opponent narrate their attempt to break free i.e. test of strength, agility etc).
As for Sneak - I get it now. I see the connection of the 'auto' description with Garrote. 'Sneak' led me down to a more traditional rpg mindset and was confused.