OK, I'm just going to spout some random opinions. I used to play quite a lot of OCC, and also played a few games with PAs enabled. PAs enabled is a completely different game of course.
Due to the need for defence, we can forget any of the early wonders. This means no pyramids and no representation. Therefore, we will get our hapiness from hereditary rule, so monarchy is a priority. Conveniently it is also a pre-requisite for feudalism. Monarchy can gain us more than enough hapiness for our needs, therefore we should delay building the globe theatre for as long as possible to prevent great artist point dilution.
Any win condition we choose can be safely left until after the PA is formed. It's best not to PA with your immediate neighbours, but more important is simply finding someone to do it with. Ideally they will be teching strongly to get military tradition (for defensive pact) and communism (PA) quickly. To get to friendly we will probably need to have either shared fave civics or religion. Religion will be random for the initial spread, but is more likely to be missionaried to us by civs with a shrine, so bare this in mind when dealing with diplomacy. Fave civics is most likely to occur from the hereditary rule guys: Hatty, Huayna, Louis, Catherine and Kublai. Alexander does have this fave civic but he will not enter a PA under any circumstances (same with Napoleon and Toku IIRC).
All non-war demands and requests from AIs should be automatically given. War requests should be thought about very carefully. Before a turnset is taken we should consider what we should say if someone asks to declare war. Getting into a war with an AI on your side will be a massive boost to getting to friendly, so should definitely be considered if the enemy civ is some distance away.
All of our first great people will need to be scientists. No dilution at all until we want to build the national epic. I am not sure about the great library - it would be nice but we will have to wait and see. We shouldn't chop too many forests for it because forests are our lifeblood (health). We start with an excellent 12 forests in our BFC - that's 6 free health.
Will discuss tech order and builds another time.
Links:
Weekend OCCs:
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An
SG I was in with PAs (immortal)