Going to my First Japanese Baseball Game?

I'll let some else answer about the tickets because I've only gone to games where friends or a league official already had tickets for me.

I have sat in the outfield seats near the "ouedan" or cheering section. Anyone one can sit there; just don't cheer for the opposing team of the section you are in.

Food vendors have a great selection outside of the park that are less expensive and often tastier than what's in the park. You can bring it into the park.

You won't need to buy tickets ahead of time as Kyocera is rarely sold out, but that is a weekend series so the outfield stands are likely to be full.

It's not really bad form to not participate in the cheering in general, but keep in mind everyone will be standing and such so if you want to relax and talk during the game you won't be able to do that. Cheering for the other team is an absolute no-no if you are sitting in the cheering section for one of the teams.

One side of the outfield is home and the other is visitor. The Hawks are a popular team so their side should be pretty full. Your best bet on seats might be to get the infield unreserved and you can sit wherever you want.

A quick look at the Lawson ticket site shows that--at least for the Saturday game--the general admission outfield seats are sold out. You might have to settle for another section. I doubt the game would completely sell out, but better to get your tickets a bit before game day if you can.