The 3.1 Update will remove  the Summons from in-world and place them in their temples.
 
  Instead of having you look for these random world encounters and the temples be like some random structure you come across I'm turning all of the thrones in world into doors that when approached will take you to the temple I've custom designed (the interior) to make look like some place you would encounter the summon.

Temple of Ifrit - Throne @ Anise's Cabin (Ifrit's ring lets followers summon him and use some of his abilities -comet)

Temple of Ramuh - Throne in some marsh somewhere (I will post where it is)  (Ramuh's ring lets followers summon him and use some of his abilities -thundaga-

Temple of Shiva - Throne in Stillborn Cavern  (Shiva's ring - lets  followers summon her and use some of her abilities -hail fires an ice spike that pushes enemies away  and rains down ice on them)

Temple of Souls (Yunalesca)  - Mystic portal at the top of Darklight Tower.
      Edea ---> will be in her temple... Illia is Edea as a follower (she has the same abilities just levels up with the character)  (Yunalesca will not be summoned by any follower but Illia, Yunalesca's necklace has only high level spells attached to it)


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Bahametta and Neo-Bahametta are only found in world from defeating a dragon, I'll probably put the spell books somewhere in world to be found or purchased

Moogle Enclave -- Somewhere in Skyrim but there is one in River Wood   (has spell tome summon moogle mage and moogle knight)

Yuna (there are two in world because I can't find the  other one) one in a temple in whiterun (that  I ddon't know the name of) wherever acolyte Jensen is and the other is in Riverwood by the dock.

Moogle Follower - Riverwood by Yuna

Carbuncle - is in the Riverwood trader