You need to experience a primal Aetheral energies to be an actual summoner. An example I'll use is from my own plot. My character is friend with the warriors of light so he got caught up in helping prevent summoning or even participate in the preparations of planning one. I Lore wise the summoner needs to experience the energies around the primal in question and also in combat. Nowhere it says you have to fight the primal directly ? Just experience it's attack (An example your own the boat where the warriors battle leviathan but your doing the driving while they do the snake fishing. Zach then researched energies in the air while they fought. Thus he came to an understanding of leviathan energies and is now working to transcribe it into material form. This is something sorta plausible and how Zach 'in a variety of ways' gathered other energies. There's more then one way to skin a cat so if you try to explain a plausible reason other then just cause then it helps out a lot. As for summoning horses. THANKS TO FREAKING ALPHINAUD TASTING THE RAINBOW! It seems with the right equations,runes, or just lucky main character prowess. Summons (like carbuncle) can have slight appearance and skill changes according to the summoner (I WANT AN OBSIDIAN CARBUNCLE DANGIT.) So maybe if you chose to make your egi like horses it'd be more accepted? Other task that can help with summoning-> ALLAGAN RESEARCH! Allagans were masters of binding things against their will to serve them and most of our abilities are from tomes from the very same folk. These are just small points i was given while working on my wiki and discussing lore. Hope it helps.
