I play E18 a lot so can speak to this a bit. For AI, China, then Aztecs have the best starts because they can expand into great land for quite awhile without much resistance. But for human, the European starts of Spain, France, Germany, and Rome are all superior by far. The key is to warrior rush the others and then you are left with four capital locations that are all stacked with resource tiles. After warrior rushing the others and then building GLH. Even on immortal level, you can launch an attack on China after killing India in the BC's playing hyper-aggressively. But if you wait until the BC's are over before expanding then your Middle East invasion will bog down at Mecca with its walls, hilltop protective longbows and a load of culture as it normally founds an early religion.
However, as AI, the Europeans will not be an issue since the AI are not coded to be hyper aggressive and warrior rush each other. France, Rome, and England are best with SIP. You are correct about Spain needing to move to the Barcelona location and Germany has several possibilities such as starting on the copper to accelerate an axe-rush.
For Aztecs, there are two schools of thought. Starting 2N gives you an HOF-quality capital location OR there is enough corn in central Mexico to have 2-3 strong cities instead of one super-city. Sometimes with E18, it can be fun to role-play history and the scenario is geared to that quite a bit. But if you just want to dominate and win then keep reading.
In summary:
1. France, SIP then warrior or chariot rush Europe. Build GLH and Pyramids then kill the rest of the world after reaching Currency
2. Rome, same
3. Spain, same except start in the Barcelona location.
4. Germany, same
5. England, bee-line Sailing, then kill France and Spain followed by Rome and Germany.
6. Greece, warrior rush Rome, build second city north of Athens on the Adriatic coast next to the copper while killing Spain, Germany, and France. Get phalanxes and kill Egypt and Persia. Then kill rest of the world after Currency.
7. Russia, expand peacefully at first in western direction then kill Europe.
8. Egypt, build 2-3 cities on Nile Delta, build War Chariots, kill Persia, Arabia, and Mali. There is also a gambit of killing Athens immediately with your initial warrior since the Greek AI is coded to build a fishing boat before their first warrior.
9. Mali - don't - unless you deliberately want to play with the most difficult start on the entire map. If so, then settle southeast of your starting place or punt your position and settle on the Nile Delta south of Thebes. Then kill Egypt when able to do so.
10. Arabia - kill Egypt then Persia. Afterwards, invade Europe.
11. Persia - start one north to grab horses in your BFC, then build Immortals and kill Arabia, India, and Egypt. Then after Currency attack China or Europe. If you decide to attack Europe, understand that your Immortals won't be effective if Greece already has phalanxes.
12. India - kill Persia, expand peacefully into Indochina. Then elepult China and Arabia
13. Japan - kill China ASAP, move your capital to Beijing, build GLH.
14. China - kill Mongolia, settle Asia, then kill Japan and India. Pick which victory condition you want to pursue. Russia will attack at some point.
15. Mongolia - kill China ASAP, then repeat history with your keshiks dominating Asia
16. Aztecs - see initial discussion, if you attack the Old World. Best place for the initial amphibious invasion is England followed by rest of Europe. Basically re-create D-Day.
17. Incas - expand across South America then attack Aztecs when able.
18. America - Monty has the initial advantage but in time you will overtake that. So play peacefully until you can kill Monty then dominate the New World. If you attack Old World, repeat Aztec strategy
