Q. Can we assassinate X?
A. You can, but you'll also incur Stress. This is what happens when you play a Compassionate character. if you wanted to murder all your political opponents, play someone easier, like Conviction.
Q. Do Primaris Marines Exist?
A. No. At least, not like in canon. Their Wargear exists, but they do not. Whether they eventually will is also not up to you.
Q. Does the Imperium suck?
A. Yes, extremely. When the opening blurb says it is the cruellest regime imaginable, I'm not taking that as complete hyperbole.
Q. Is the Imperium necessary?
A. Only as far as it has made itself necessary. While there are many interpretations based on canonical texts and also within and between Codices, for this quest the answer to this is a flat No. The Imperium did not need to exist in order to ensure humanity survived the Age of Strife, and in many regards was one of the worst solutions that the Emperor could have conceived. That is the point. You're here to guide the cruellest regime possible in the service of good while trying to change it for the better in the middle of a great galactic crisis, with all that implies.
Q. Can Pandora create Space Marines from her own Gene-Seed?
A. No and never. Pandora already has two options for equivalents: her own Deva, who are basically flying teleporting respawning Space Marines, and an Order of Sororitas, who can eventually match Space Marines thanks to having reliable faith powers.
Q. Can we kill the Chaos Gods?
A. Not in the timeframe of the quest, no matter what you do. In fact, don't expect to kill any even in an epilogue. If the Anathema and all the Eldar Gods failed to kill three sleeping ones in millions of years, you definitely won't do it in a few hundred years.
Q. Does Pandora gain stress from X
A. Generally, Pandora gains stress from two different sources: shocking revelations from the past that hurt her friends, family, and other people she cares about, and acts of wanton and unnecessary cruelty that trigger her Compassion virtue.
However, also note that, much like people in real life, Pandora can and will grow numb to certain forms of trauma. She's not going to gain stress from the concept of people starving, or from wandering the Underhives and witnessing the squalour there again. But she will gain stress if she's made to listen to people getting tortured to death with no way to save them, or if she's made to discover yet more shocking truths about her family, or if she's forced to make sadistic decisions like commit murder for the sake of the greater good. With exceptions: however, at best, these will be stress neutral.
Q. Does Pandora lose stress from X
A. Similarly to the above, Pandora's stress relief generally comes about from two sources: opportunities to unwind and process her feelings in the form of time off or relaxation actions, which will be appropriately signposted, as well as moments of normality where she can act like she wants to instead of like she's expected to around her friends and family, which is the source of the passive stress reduction that people like Lily and Tor Garadon provide.
Things Pandora does not gain stress relief from include: murder, genocide, torture, implied torture, the threat of violence, the use of violence, revenge, and revenge fantasies. Pandora is a kindhearted girl who does not enjoy violence, for all she is very good at delivering it. She also has the Compassion Virtue, which means that she quite literally won't take pleasure from killing even her worst enemy. That is simply not how it works for her. So keep that in mind if you're going to suggest Pandora might gain stress relief from killing X monster or Y character, because the answer is generally that she'll gain stress.
Q. How many Exalted/Exalted Equivalents do the Chaos Gods have?
A. Chaos Gods have two types of Exalted Champion; Exalted Greater Daemons and Exalted Daemon Princes. Each Chaos God is limited to their Holy Number in Exalted Greater Daemons, which naturally gives Tzeentch an advantage - or would, if not for a certain theft that a certain Archdeva of Pandora's performed.
Exalted Daemon Princes, meanwhile, are as the name implies Daemon Princes that have grown to match the Exalted Greater Daemons not only in power but in esteem as well. These are not capped by the Holy Number of a Chaos God, but have a different limitation; Exalted Daemon Princes are essentially unique, for it is extremely difficult to find a mortal soul capable of containing that much power and retaining their sanity.
At the start of the quest, Tzeentch had 8 Exalted and 1 Exalted Daemon Prince; Khorne had 8 Exalted and 2 Exalted Daemon Princes; Nurgle had 7 Exalted and 1 Exalted Daemon Prince; and Slaanesh had 6 Exalted and 1 Exalted Daemon Prince.
Notably, the God-Emperor of Mankind has 5 Exalted; he has no Exalted Daemon Princes, in theory, as one can technically consider beings like the Sanguinor his Exalted Daemon Princes.
Q. Can Pandora get more Exalted?
A. Pandora is not a Great God of the Warp and is already bucking the curve by having an Archdeva (an Exalted) at all. However, she might gain one in the future. Past that, however, more are unlikely, except for a certain action that can grant Pandora immense power...
Q. Why was Turn 1 so long?
A. Bad time management. A lesser man would try to claim that it reflected Pandora's inexperience as a Lord Commander, and that's why later turns streamlined as she got more experienced and accustomed to the job... But no, it was all me. I'm to blame.
Also, you guys went on crusade to the Dark Imperium. Of course it was going to last forever.