οὕτως εἶχε τὴν γνώμην ὡς ἤδη παντελῶς κεκρατηκὼς καὶ οὐδὲν ὄντα τὰ τῶν πολεμίων.
Is this οὐδὲν ὄντα τὰ τῶν πολεμίων is another Acc abs, or is just the copula missing?
Just another acc.abs., as at 6.1.10 etc.
How do we know that it’s accusative? In οὐδὲν ὄντα τὰ τῶν πολεμίων, ὄντα agrees with τὰ τῶν πολεμίων, not οὐδέν.
The phrase could have been οὐδὲν ἦν τὰ τῶν πολεμίων, with finite verbs following the ὡς. But since the first branch was drawn into a nominative participle by the normal continuance of the subject of εἶχε (maybe aided by the idea of perception with γνώμην) that ἦν naturally turns into a participle (nominative) following the construction of the first branch.
I think not.