I’m actually going to go through these point by point from a worldbuilding perspective, because that’s the kind of nerd I am. So for the purposes of this post, we’re assuming we live in the AU where the Macbeth curse is inarguably real and magic is consistent and can be analysed systematically like this.
The first thing we have to decide is precisely how the magic works; it could be the intent and awareness behind the utterance, or the simple act of speaking, or the syllables themselves.
If it’s the sound itself, then the parrot can cast the curse, as could the recording and the person on the other end of the phone, but the sign language and the social media posts would be inert.
If it’s working on sound alone like this, then translated quotes from the play would not cast the curse, nor would paraphrases or misquotes, but strings of text that are contained within the text of the play and spoken (or played) out of context or without an awareness of the phrase in the play would also cast the curse. Every instance of “who comes here?” and “God save the king” and “good morrow, noble sir” and “knock knock” would cast it. So, since Hamlet and knock knock jokes do not carry a similar curse, we can rule out the sound only method, at least for quotes.
If the magic works on the speaker’s awareness of the context of the utterance, then the parrot and recording can’t cast it, but the sign language should be able to. The phone might work, if the caller is aware that their voice is being transmitted into a theatre.
The person in the theatre should most likely be able cast the curse by posting to social media or sending a text message.
Reading a post social media post might work, depending on the OP’s awareness that a potential reader might be in a theatre. Same with reading text messages.
However, by this method one could theoretically think “Macbeth” hard enough to cast the curse without actually saying anything, and a text message or social media post could cause one to do so. (If you’ve read American Gods, there’s a bit where a character thinks “snow” hard enough to make it actually snow. If the Macbeth curse works on thinking “Macbeth” hard enough to fit that thought to speech, then it could theoretically work without any speech involved at all, at least for certain magically inclined persons).
If it’s the act of speaking – the act of tying the thoughts to the words – then, like the awareness/intent method, the parrot and the recording do nothing while the sign language and text in translation are effective.
Receiving it as a text message or viewing it on social media would likely do nothing, the sender/OP not tying the thought to the world while being in a theatre, but if you sent or posted the text from the theatre it would depend on how your thought-to-text process and how closely that mimics speech.
Small tangent: when I type, I think a thought and as I fit the words to the thought those words spill out my fingers in almost exactly the same way spoken words spill off my tongue, so I’d consider my own typing to be an “utterance” and capable of casting a speech-based curse like this. But when I write by hand or use the touchscreen keyboard on my phone, it’s not as fluent and not as similar to speech, so I could cast the curse by typing on a laptop, but not by writing on paper or sending a text message from my phone. Different people would be able to cast it using different methods.
The phone is again a bit trickier, and might work if the caller knows you’re in a theatre.
On to what counts as a theatre for the purposes of the curse.
There would have to be something magically different about a space where plays are performed that would affect magic, sort of how how churches are consecrated and assorted gooblies can’t enter them, or how vampires can’t cross thresholds of homes without being invited. Conceptual lines are drawn between or around spaces to mark them out for certain purposes, and magic does different things within different space. Like how temperature influences what water can do (eg, be solid or liquid), the presence of a threshold line or inside-a-theatre-ness would influence what magic can do.
A non-theatre space being temporarily used as a theatre would pick up a sort of temporary consecration (I don’t think I have a secular term for the concept, so “consecrate” will have to do) that would make the curse work when it is determined that it shall be used for a production, or when the rehearsals or other production-related activity starts there, and then afterwards the consecration would dissipate as the production infrastructure is removed and the space is used for other activities. Or at least, I’m assuming it would. It is possible that the threatre-ness would linger, at least for a time.
What about buildings that used to be theatres and are now used for other purposes? Does the curse work in them? And how about land that used to have a theatre built on it? How does a space become a theatre, for curse purposes, anyway?
I would assume that when a space is intended to be used for productions of plays, it picks up a bit of theateryness from that intention, more depending on how distinctly the space is delineated (so buildings get the most, since they’re delineated by solid walls and roof, and meadows and naturalistic parks get the least, since they don’t have solid lines), and then rehearsing and performing and watching plays in that space creates more theateryness, until there’s enough for it to heavily influence magic. Then, after a building is torn down or abandoned or repurposed or a production moves on from a temporary the space, theateryness would begin to dissipate, and it could be thoroughly gone within days (for a single short-lived production in a poorly delineated space) or it could take centuries (for a building which was a popular theatre and busy theatre for ages).
The real question, and one I don’t have an answer for [yet], is how or if Skype readthroughs create ground for the curse. Can the curse be enacted within non-physical cyberspace in the skype group itself, cursing the readthrough with skype ghosts? If so, would if affect readers’ internet or computer programs in other ways, or just within Skype? Or does each participant’s computer or desk pick up just a tiny bit of theateryness for the duration of the readthrough, and if so, how quickly does it dissipate, or would monthly readthroughs accumulate theatreryness until, after a couple of years, someone’s living room is a full on theatre for curse purposes?