The Lunar Ruins possibly wasn't ported to the DS remake, hence the title, "GBA- Exclusive."
After finishing Final Fantasy IV Advance, there are a number of things you can do. You can explore the Lunar Ruins. There are 10 different trials in the Lunar Ruins, each resulting in a weapon or item or great importance. You can also travel the worlds and fill up your bestiary, if you haven't already.
No
Its right by the chocobo race track.
At the chocobo circuit you fallow the wall on the right.
Go talk to the little yuke in village.
You can find Tonberries at the Cavern of Stolen Fayth, and Master Tonberries at the Omega Ruins.
The DS version was more focused around developing your five main characters fully by using the augments, and by having a new game +, and then a new game ++. The lunar ruins on the other hand was part of the GBA version, which allowed you to use most of the temporary characters again, and had ways of developing them. The two systems didn't really mesh. Having the main characters get the augments didn't really mix with one where the old characters could still be used. Taking your main team through the game three times didn't really mix with having to deal with 10 characters and a huge dungeon where virtually none of the items you got could be carried into the new game +. So they went with the exclusive Augment system and dropped the GBA Advance version's specific areas.
If you go one way or another you should go p some stairs, somewere along them should be a vase or something of flowers. Tidus uses them as tinder
The Archeoaevis will frequently change its resistances during the battle, so a spell that damaged it before could end up healing it. If you cast Scan though, you can see what it is currently weak or resistant to. When you defeat it, it revives itself. This form can be slain instantly with the Blue magic spell 'Lv5 Death'.
Curseproof is an ability that you can either find on an armor that already has it or customize it onto a different Armor. The Master Coeurl in the Omega Ruins will sometimes drop armor with Curseproof on it. Otherwise, you can customize Curseproof onto an armor with 12 Tetra Elementals, which you can steal from the Master Tonberry (Omega Ruins) or the boss Seymour Natus (Via Purifico).
To access the other half room of Ruins 5, you need to go through Ruins 6 and 9 before reaching there. But the door in Ruins 6 is locked. To unlock it, change the switch combinations to:- Left, Right Right, Left
you have to fall when approached the mobile platform and for the final item you have to get to the end of the ancient ruins