I think that the only ones more powerful than Jinsung in the Family are the Twins ie His parent and his parents Twin. As far as we know they're both women apparently, so only his mom and his aunt is possibly more powerful than him(if we exclude Yurin). Then of course we can start to discuss the children from the other twin(his aunt) and how powerful her children might be compared to Jinsung. Of course we could make arguments for all 3 possibilities ie they're "equal", theey're "weaker" or "they're stronger", but we just don't know. I personally think Jinsung ranks higher in the family than anyone in teh family except the twins and the FH herself, the old "pride" of the family that Yurin dragged around everywhere, even to Jahad himself.
Army of what, normal regulars and low rankers? No princess shown so far impressed me enough to think they could take on the High Rankers in the families, even some of the High Rankers from the Families we've seen so far.
Other than perhaps Adori and Enne(Though I doubt she'd ever help Jahad if she's freed again) I can't think of any princess that can even stall Dumas alone, let alone face the rest of the army's numbers.
Yuri hung around Urek too long, starting to make stuff up to make herself appear more important than she really is, trying to justify their "princess system" and position. I doubt the princesses alone can take on the combined armies of the ten families. I don't they can even take on the combined armies of 2 families. If we're talking about the army of 1 family though, then maybe we can have an interesting show off especially with Adori there but I think they'd find it far more difficult than they thought.
Yuri would definitely be the first to activate 2 great months at the same time again, once again falling victim to the madness that comes from it, and this time there is no Garam or Bam to save her.