Blue Dragons can drop Dragon Fangs at any level. Infact, it's better to have them at a higher level, since they drop more (8 to be precise) at their higher levels. Alternatives include low level Grendels, low-mid level Hexdragons, mid-high level SAM08Gs, and mid-level T-Rexaurs (rare drop only).

In regards to AP gaining, there's really nowhere better than Cactuar Island. Have Squall on his own with Auto-Haste and junctioned Speed (Triple is best for this). Any AP gained is given to every GF, as oppose to Exp which is divided. Gaining about 10~30AP per battle, you'll probably have every ability learned within a couple of hours, maybe less.

As for the Elnoyle guy, he's found on one of the connection bridges that the Lunatic Pandora crosses over. If you miss him then you can find them inside the Lunatic Pandora, or on the lowest levels of the Deep Sea Research Centre. An alternative method to finding the Energy Crystals from Elnoyle is to get them from mid-high level Behemoth's. They can be found at Tear's Point while the Lunatic Pandora is over it, or again in the lower levels of the Deep Sea Research Centre. You can also get them by refining twenty Elnoyle cards, which you can get quite early on in the game.