The world emigration is square's attempt to balance out server load. They are basically giving players on certain servers the chance to move to a preselected. If you do not wish to move your character, just ignore the message. If you want to go to the other server, just go talk to the world shifter.
As for fruit seeds, the only place I've successfully farmed them is in crawler's nest. I know you can supposedly get them from logging outside of Sandy, though I've never had any luck. They are just below tree cuttings in the pain in the butt to farm department and equal to tree saplings in the pain in the butt to grow. However, the income from them can be quite nice.
Here is a list of how to get the seeds according to another site.
Dropped from Mobs:
Stalking Sapling (Batallia Downs) (Level: 20-24)
Caveberry (Crawlers' Nest) (Level: 42-44)
Leshachikha (Lufaise Meadows) (Level: 49-53)
Cherry Sapling (King Ranperre's Tomb) (Level: 62-64)
Boyahda Sapling (Boyahda Tree) (Level: 74-77)
Leshonki (Boyahda Tree) (Level: 79-80)
Stolen from Mobs:
Stalking Sapling (Batallia Downs) (Level: 20-24)
Caveberry (Crawlers' Nest) (Level: 42-44)
Witch Hazel (Crawlers' Nest) (Level: 50-52)
Boyahda Sapling (Boyahda Tree) (Level: 74-77)
Obtained by Chocobo Digging in:
Ronfaure East (Very Rare)
Obtained by Logging in:
Ronfaure East (Very Rare)
Buburimu Peninsula (Very Rare)