Anyways, I'm going to rank the Neo-leaders based on what we currently know and scaling off the current manga tierings. Might as well see how wrong I was 5 years from now. Starting from the bottom...
12. Infelsinave, (below wolf without suit) high tiger with suit, (10-B) High 8-C.
11. Zaedats, (below wolf), high tiger with suit, (10-B) High 8-C.
Infelsinave and Zaedats are equipped with suits that should equal or surpass those of the regular neo-heroes, who are noticeably stronger than High 8-C Great Philosopher. But they're pathetic without their suits and helpless against demons even with them.
10. Ryumon, high tiger and a-class level, High 8-C.
9. Accel, high tiger without suit, low demon, (High 8-C) 8-B.
8. "A", high tiger without suit, mid-demon, (High 8-C) 8-A.
Ryumon should be around that A-class level as well, he did well against a tiger. Accel would be top five A-class in my opinion, probably about the same level as Suiko with his suit. A is more impressive, has an A-class bounty even before he puts the suit on. Got some praise from Sonic in their fight as well.
7. Metal Bat, (high demon (base)), low-dragon, (High 7-C) low 7-B.
6. Suiryu, (high demon), low-dragon, (High 7-C) low 7-B.
Suiryu is pretty straightfoward, keep in mind I'm not taking fighting spirit into account for Metal Bat since we have yet to see the full extent of that. I'd guess the suit + fighting spirit could be 7-B, 7-A maybe.
5. Blue, low-dragon, low 7-B.
4. Child Emperor, mid-dragon with all his tech, 7-B.
Blue beat the demon-level Crab-king no problem, but struggled to put down what looks like a low/mid dragon to me. Said dragon was also probably kill-switched by the organization for the sake of their neo-heroes publicity campaign. Not very impressed by the son of Blast yet, but I'm sure he'll get stronger as he gets older and more experienced.
3. Webigaza, mid-dragon, 7-B.
2. Raiden, high dragon, 7-B+.
1. Darkshine, high dragon, 7-B+.
I put Webigaza behind because I think the Organization has her stalking Child Emperor the same way Erimin and Destro (who are probably mid-dragons themselves) are creeping on Metal Bat. As such, I think she's strong enough to defeat Child Emperor even with stuff like Brave Giant. But this assumes things will stay roughly the same in the manga continuity.
Raiden is technically the strongest neo-leader, assuming his grappling with Darkshine is actually a sign they are roughly equal. The fact that he feels a neo-leader suit, which can amp up someone like Suiryu into low-dragon, is too weak for him is a sign for me that he's at least a dragon. I feel like his arc with Darkshine will end when Darkshine regains his confidence and beats him in a competitive rematch, making him a high dragon around Carnage Kabuto's level. But his durability, I assume, is not near above-dragon like Darkshine.
Darkshine isn't technically a neo-leader but I've thrown him here in anyhow. Assuming Darkshine will follow the above redemption arc, I think he's going to be stronger than Raiden in the end.