no
You can buy them with points from battle tower or find them as items or get a Pokemon with pickup ability at a high level to find them
lost tower at night
go to your lost tower
its in the tower by solaceon town
that's how you find hidden items
Lost Tower, just south of Solaceon town.
You can catch Duskull in Pokemon Platinum by going to the Lost Tower that is near Solaceon Town however you can only find it at night.
You can find TM53 energy ball on the battle tower and on route 226.
well, you can see a trainer with it in the battle tower/battle foniter
Yes, your Pokemon may find items after battling wild Pokemon or trainers, but it will not find items inside special event battles such as the Battle Tower.
Yes. you can find ghastly at lost tower or Eterna Forest. You can get haunter but i don't know where.
In Pokemon Ruby and Sapphire at the top of Sky tower after the Pokemon league emerald before the Pokemon league Diamond, Pearl and Platinum you have to migrate from the GBA Games (Sky Tower is near pfialog)