My reasoning, some of which has been edited slightly along with the plan:
[ ] Plan: Know Thy Archenemy
And here is my plan. Anexa was shifted back to school after some clarifications. Mostly differs from Alectai's in that mine has some actual blueprints in it, instead of just more fundamental research (Alectai's differs in having combat-bot humanization, I think). Write-ins are also a bit different, but both are in a very similar vein to their messages. I'm honestly fine at this point with his plan winning too, but I'd still like us to have also some spy satellite's and heavy fortifications so posting my plan.
[X] Plan: Know Thy Archenemy
-[X] [Free] Poke around some more in the databases, looking for anything in particular.
--[X] What is the deal with this God-Emperor anyway? It sounds kind of crazy, and there's got to be more to it, right?
-[X] Construction (900 GBP)
--[X] 1st construction slot (900 BP):
---[X] 4x Manufactory (100 BP, 50 CP)
---[X] 6x Underground Anti-Air Defenses (aboveground base) (75 BP, 5 CP)
---[X] Trade goods, Aevon (requested weapons) (50 BP) (Trade goods, Aevon 55 -> 105)
-[X] Research x3 (600 RP)
--[X] 1st research slot (200 RP):
---[X] What's up with this tech? (100 RP)
---[X] In-atmosphere void shields (100 RP)
--[X] 2nd research slot (200 RP):
---[X] Basic Imperial Hacking (150 RP)
---[X] Blueprint: Spy satellite (25 RP)
---[X] Blueprint: Anti-armor Bunker (25 RP)
--[X] 3rd research slot (200 RP):
---[X] Let's fix the lag issue (50 RP)
---[X] System survey (50 RP)
---[X] Mechanicus files on the Archenemy (100 RP)
-[X] Pay rent (Trade goods, Aevon: 105 -> 80)
-[X] Anexa passive action: Education - Roll to level, difficulty is 10+5xLevel
-[X] Anexa: Juvenat Yes
--[X] Write-in: Tell Anexa about the various worlds, ideologies, organizations and people that you saw embracing cybernetics, both the good and the bad. As well as about one of your crew, who was a near full-conversion cyborg. Tell her to make her own jugdement if cybernetic ascencion is what she wants based on this information. And with enough time, made easier by the juvenat.
-[X] Aevon Mine: Take the "mine disguise" deal
--[X] Write-in: Mention that as you are still increasing your manufacturing capacity, it has resulted in your anti-air and anti-missile defenses lagging somewhat behind the ideal state. Just to avoid any misunderstandings about what they can expect from you currently if they are planning something. Promise to keep them posted
roughly on the capabilities of your protective umbrella as it is built up (but not the exact details), if they keep you in return informed about any...
Aggressive moves they might take in the future.
-[X] Aevon Weapons: Yes