I have Tawnos, Urza's Apprentice as my commander for a deck I'm building. And looking over Phyrexian Revoker I wondered if I could copy its ability and name a second card as it comes down to lock down 2 potential threats. And since Stuffy Doll is written the same way, Could you name 2 players and have them both linked to Stuffy Doll?
No, that does not work. Those abilities are not activated or triggered abilities, so Tawnos can't copy them.
Phyrexian Revoker and Stuffy Doll have abilities that start with
As [card name] enters the battlefield...
These are replacement effects, as specified in rule 614.1c:
Effects that read “[This permanent] enters the battlefield with . . . ,” “As [this permanent] enters the battlefield . . . ,” or “[This permanent] enters the battlefield as . . . “ are replacement effects.
Tawnos's ability's effect says
Copy target activated or triggered ability...
So it doesn't copy replacement effects. Replacement effects do not go on the stack, so other cards can't copy them either except by copying the whole creature.
Besides them not being classified as "triggered" as murgatroid99 points out, there would still be
607.2d If an object has an ability printed on it that causes a player to “choose a [value]” and an ability printed on it that refers to “the chosen [value],” “the last chosen [value],” or similar, those abilities are linked. The second ability refers only to a choice made as a result of the first ability
So even if you were able to copy the ETB ability, doing so wouldn't do any good; the static ability would refer only to the last chosen value (since the stack is resolved in reverse order, that means that whichever choice you made with the first copy that you put on the stack would control the static ability).