15 Kryptonians, even the scrawny ones like that one guy, are still going to be beastly. However, what I was getting at earlier is things like this:
They have A LOT of fodder to distract them with.
Welp, I decided to stop being lazy. You can count the number here. And can still spot Nam-Ek's big ass in the background, even without his armour:
11 flying penis pods.
Well, the OP says it's at the lighthouse, so that's next to the ocean. And I don't know how many Atlanteans contributed to this feat in total, but, seeing as they are all included, it probably doesn't matter all that much.
Mera can manipulate a fair amount on her own though as well. Actually a few decent strength feats for Arthur in there as well, batting the trees away.