Alright, starting from the right, because, why not?
Shingo Takagi (aka SHINGO) is pretty much a huge part of DG's future. The man has been on the rise since 2005, and is only getting better. He was part of Blood Generation ( CIMA, Don Fuji, Naruki Doi, Masato Yoshino, Shingo, and Magnitude Kishiwada), and not too long after Blood Gen died, he spent a year in ROH. When he returned to Dragon Gate, he started New Hazard (Shingo, BxB Hulk, Cyber Kong, and Yamato.)
On a bit of a sidenote, GAMMA was in Blood Gen near the end, and he clashed with CIMA constantly. This ultimately lead to Doi, Yoshino, and GAMMA leaving (and Magnitude joined them later.) They beat CIMA, and a few others (I want to say SHINGO and Jack Evans, but don't quote me), to win the rights to the Blood Generation name, at which point they trashed it, and created the Muscle Outlawz stable.
Second from the right is Yamato, who is the rookie of the group, but a damn good rookie he is. He entered New Hazard very early into his DG career and just blossomed. Not too long ago, he betrayed New Hazard and joined the Muscle Outlawz. He has an interesting persona, as he sort of plays this wild, almost psycho type of wrestler, who looks crazed half the time, seems a little off, and will pretty much fight anyone. While it's a huge stretch, the closest thing I can relate the persona to is that of Brian Pillman's Loose Cannon gimmick.
Geniki Horiguchi is next. To be honest, I was never a huge fan of the guy until he turned on Ryo Saito, left Do Fixer, and joined Muscle Outlawz... Hell, he went from looking like a lame wannabe surfer, to amazing badass. I mean, check it out.
Before
AFTER
Unfortunately I couldn't find a better pic, so you can't see the bizarro blonde hair he has in the back with blue weave... Still, he's pretty slick now.
Anyway, Genki is incredibly solid in the ring, and he plays the heel great. Plus, any guy who can make a backslide legit, is okay in my book ( As a face, he did a backslide that was called "Backslide from Heaven" which was his near inescapable backslide. When he turned heel, they started calling it the Backslide from Hell, and it was usually preceded by a low blow.
Next is Yashushi Kanda, who I don't know a whole lot about. He career was cut short early on, and he ultimately retired, and became a ref. He was a heel ref, helping out his old stable. Eventually, after many assaults from the Muscle Outlawz, he returned to the ring in 2006. Ultimately though, he joined Muscle Outlawz. In 08, he was key in the downfall of the group though, as he was a major player in the strife between the group and Doi/Yoshino.
Now we have Cyber Kong (yes, the guy with the muscles painted on.) Honestly, he hasn't done much, but he's decent in the ring, and plays the powerhouse very well. Plus, in good powerhouse fashion, he has a tendency to lose to quick pins out of nowhere.
Finally, there's GAMMA... Fucking GAMMA. Probably the best heel in Dragon Gate right now. Charisma wise, he's pretty much the second coming of CIMA. The guy is easy to hate, and it makes it easy when he does things like stand on the top rope and drink water, and then spit it down onto a fallen opponent, or spit in his hands and rub it into his opponents face/ hair before pummeling them in a corner. Plus, he does a crucifix powerbomb setup into a facebuster, which is just badass. He was also key in Muscle Outlawz ending, and the whole thing started when he assumed leadership of the group while Naruki Doi was out injured.
That's the rundown on the wrestlers. Naruki Doi and Masato Yoshino basically left the group/ were betrayed on the last show. There had been a lot of infighting between them and the ret of the group, and it boiled over at the last big show, where Genki and Kanda basically turned on Yoshino. With the help of Doi, Yoshino came out of it okay, and Kanda ended up getting his head shaved.
As far as who's leading the group, most people believe it will be GAMMA and Shingo leading the group together. I really don't see Shingo going into a second fiddle role, mainly because he's grown so much, it won't work... Although unfortunately for him, GAMMA has enough natural charisma where, overtime, he'll probably be the perceived leader.