Ah, I remember when I had issues getting this thing. Basically you need the weather to be clear, no wind at all. When its clear, you'll be able to encounter it.
Pfft, Sableye guys.. come on. In all seriousness, Swagger is a great tm, both useful in singles and doubles. I like it, and can't wait to make use of it on gym battles/bosses/FERN
http://www.pokemonreborn.com/game/pickup.html <- May take awhile to load, be patient. The pickup tables are customized for Reborn due to level caps n other stuffz.
Yep, and I believe Geodudes also have the chance of holding onto it.
EDIT: Gravelers and Golems as well, but no way we're going to find a wild Golem... hopefully..
Bingo. Zubat has been replaced and can be found as soon as you get to the Wasteland. Noibat is eh, it shines when it evolves into the glorious Noivern.
*break everything* Seriously, they do deserve a new arena. I believe there was a discussion about a bug type field effect, so maybe that horrific aspect can be added to it. For Shade, if a pokemon is asleep, they take damage, like Darkrai's ability.