The idea of Ewoks having weapons on hand makes sense if they have had run ins with the Imperials before.

But the idea of a past conflict should probably be limited to one shot. Someone a while back had the idea of a rusted burnt out AT-AT.

That would be very cool. Or perhaps more credibly, a scout walker(if they've already been established to that point).

The thing I like about the AT-AT shot though is we know how powerful the walkers are from the previous film and to see one burned out on the forest moon would likely make the rebels say "what did that?".

You could even reorder the end scene of the ewoks with the imperial helmets as drums and put it into the heroes arrival at the village for dinner.

So if the Ewoks have weapons already to go then that would mean perhaps a attack is imminent or they're protecting their village from a threat of attack.

Maybe the Ewoks plan a last-ditch assault on the Imperials, the rebels see their outmatched, and so they join forces?