If a TAG is isolated, and then possessed, what's the rules interaction? ie. can orders from the hacker's pool be spent activating the TAG?
Yup, congrats on having possessed a TAG you will need to take an engineer close to so you can spend orders on. So if you plan to possess, make all hacking programs to attempt Overlord and/or total control :p
Isolate: While Isolated, troopers cannot receive Orders from their Order Pool. Possessed: Troopers in this state cannot activate or receive Orders from their player's Order Pool. Possessed troopers may be activated and receive Orders from the Order Pool of the player who caused them to enter the Possessed state. The Possessed trooper can only receive Orders from the Order Pool of the same Combat Group as the trooper who caused the possession. I see no reason why Possessed troops who are Isolated cannot receive Orders from the Order Pool of the same Combat Group as the trooper who caused the possession. Edit: which gets weird if you Possess your own TAG back.
"Their Order Pool" means "the order pool from which they can receive orders". Still and Order Pool. Still unable to receive orders from there.
Your stating an interpretation as fact. The alternative interpretation I outlined is just as viable: the language is relatively ambiguous. @ijw thoughts?
Semiotics talks about 'available readings', 'simple readings' or 'strenuous interpretations' that aren't impossible and might arguably be plausible, but require additional provisions or plausible reasons why exceptions are being made to expected meanings. The simple reading of here is that when Possessed a TAG has changed controller, got itself a new profile, and now uses that new controller's pertinent Order Pool. And that if it's then subsequently Isolated, 'their order pool' refers to the new controller's pool, because that's what Isolated usually does to a non-possessed unit and we don't have to make any exceptions or strenuous arguments. So it's not impossible to provide an alternative reading that somehow makes the original order pool available, but one also has to make additional arguments for why the word 'their' from the Isolated text has changed meaning from 'the Order Pool that can (currently) active this unit' to 'the Order Pool that used to be able to activate this unit, and from which it was Isolated'. If a Possessed and Isolated TAG were indeed Possessed back (which might not be too much of a stretch given a good Hacking army and a mission in which the TAG were more useful re-Possessed than destroyed) then again the simple reading is that it'd use the Order Pool of the Combat Group that did the re-Possession. But whatever; players can make more strenuous readings if they want to.
Because 'their' can mean 'the Order pool of the Combat group to which they actually belong' which never changes. Which honestly seems a far simple reading than 'their' changing potentially several times in a turn.
No bleeping chance. It's Isolated. Note that Possessed state uses the same phrasing for both players: 'their player's Order Pool' 'the Order Pool of the player' So anything that affects Orders for an unpossessed TAG should affect spending Orders on it when Possessed.
So, long story short, "Order Pool of the player who cause Possessed State to troopers" is considered to be "their Order Pool" in that scenario?