I don't really understand the question, but I'll try my best to help.
If you want to pregenerate a world, you can use the WorldBorder plugin. Upload your (not fully generated) world to the server, set the world border (not the default Minecraft worldborder, but the plugin's one), and run the specific command for pregenerating the world after it. It will take some time.
If the original world that you upload is made with worldpainter the new chunks generated will be vanilla terrain.
You can use a world generation plugin though, such as EpicWorldGenerator for your world, and than the worldborder plugin pregenerate command will generate EpicWorldGenerator terrain.
And remember, make backups of your world, as if you do something wrong, it will screw up your world, and you have to delete chunks in MCEdit.