I would think you will definitely be cutting it very close, if you even make it in time. We've been to Ohana's with a large group several times and those times I would say the meal lasted close to, if not a bit over, 2 hours.
What time do they start seating for dinner? I always thought they started seating at 5pm. The extra 5 minutes wouldn't really help you in this case. Perhaps they start seating earlier and I'm just unaware of it.
Resorts we've stayed at over 17 trips: ASMo, ASMu, ASSp, PC, CSR, CBR, POR, POFQ, WL, AKL Jambo, AKL Kidani, Poly, BC, YC, BWV, OKW, SSR, Swan, Shades of Green, Vero Beach
Next Trip: Maybe Food and Wine Festival in Oct.