Navarro came to the Royals from the Red Sox in a trade for Mike Aviles. It's hard to get a read on his hitting ability because he has played at several different levels in all of the last three years, but he held his own at Class AAA as a 23-year-old, so he's probably not a complete zero with the bat, and scouts seem to like his hitting ability. His defense, however, isn't highly regarded. He'll need to be added to the 40-man roster. He can play a bit of shortstop (although it doesn't sound like he's the kind of guy you'd want there for more than a few games) along with second and third, and the Red Sox also had him try playing all three outfield positions, so there are lots of ways he can be useful. It's not yet clear where he'll fit in with Chase d'Arnaud and Josh Harrison, but this might be a case where the Pirates figured they could cheaply get a guy who has a bit of power potential, and they'd sort out the details later. Here's a good scouting report. There are mentions of issues with his work ethic and/or lapses in concentration in everything I've read about him so far, but his offensive upside definitely makes this a worthwhile move.
You know about Pounders - he's a big guy, but he doesn't have great stuff. He had a good season in 2011 as a reliever, but he's far enough down in the low-minors pecking order that losing him is no great loss. Goris hit very well (.350/.387/.511) in the DSL last year, but he was old for the level, and I've never heard him described as a top prospect. He may simply be someone the Royals' scouts want to take a flyer on.