If Davis & Johnson have great years, sure they can make the Pro Bowl. They're both capable, but the odds seem to favor AJ rather than DD because of the competition each face.
Last years AFC Pro Bowl RBs (Lewis, Holmes, & Portis) averaged almost 1700 yards & over 18 TDs. That's not even including Tomlinson who had over 2300 yards total offense. Plus, there's good RBs like Fred Taylor, Shaun Alexander, Ricky Williams, etc. that watched the game on TV. Domanick should be in the mix, but the competition for a RB in the AFC is brutal.
Last years AFC Pro Bowl WRs (Harrison, Chad Johnson, Mason, & Ward) averaged around 90+ catches, 1200 yards & 10 TDs. Good numbers, but nothing that Andre isn't capable of. There are other good AFC WRs as well such as Santana Moss, Seattle's Jackson and Robinson, and Miami's new combo of Chambers & Boston. But taking note of his clear #1 WR status and talent, and I like AJ's ceiling more than most of these guys.
When 2 players stats are close, the Pro Bowl bid usually goes to the guy on the winning team. When the Texans begin to win consistently, AJ & DD will be routine visitors to Hawaii. Who knows, maybe this season is the beginning of that trend.