FFX-2 is good if you enjoy minigames. The RPG element of it only comes in during the battle scenes pretty much. Don't be put off by the way I describe it though, it's a very good game that will allow Yuna to explore Spira without the linearity of FFX.

Mar Crest is Auron's crest. Used to half power his legendary (but not necessarily the best) weapon, Masamune.

Withered Bouquet has already been used. At the beginning of the game, Tidus lights a fire in Baaj Temple before Rikku storms in and takes him away. The bouquet was used for the fire. That's it. I dunno why he still has it.