To pass inspection? What inspection? Is it a sealant just to, say, keep exhaust fumes from getting into the car? Or is it a structural thing to keep your feet from Flintstoning?
If it's just the exhaust type sealant, and it'll all be removed for a proper job later, you might try the spray foam insulation, that yellow "Great Stuff" foam from Home Depot.
You'll have to spray it on, let it cure, then trim it down, or try to weight it so the foam expands "outside", but either way, you'll have a reasonably airtight, watertight seal.
I did it to the trunk floor of my Cutlass. A leaky rear window seal let water flood in over the years, and while it didn't linger- thanks in part to the cutaway fenderwells- it still ruusted the floor badly, and it was full of holes ranging from pin to gaping.
I'll be replacing it all, either with a stamped trunk floor kit, or just raw sheetmetal (since I'm not trying for a restoration) but that won't be 'til summer. So for the time being, I filled as many holes as I could with the spray foam, to keep out any road spray or debris, and to cut down on the road noise. (I said some of the holes were "gaping".)
It made a big difference on that latter point, actually, though when you open the trunk, it looks like a giant diarrhetic turkey spent a week in there, but hey, it works for now.