can lugia and hooh deafeat arceus when lugia has its orbs and hooh secert 火災, 火 and arceus plates

Okay technically they have the POTENTIAL to defeat Arceus. But in all honesty it depends. For one thing, if Arceus is using the Zap Plate, then it could easily defeat both of them, seeing as they're part flying and electricity is supereffective on Flying. Plus, then Judgement would get the STAB since both it and Arceus would be electric types, and the Zap plate would further increase its power.