I actually stayed up last night thinking about the bros weapons in that solarpunk/steampunk verse and came to the conclusion that I desperately want to keep the hammers. so yeah. hammers.
the way marios hammer is designed he can light it on fire anytime. luigis is actually pretty tricky bc electricity isnt as straightforward as fire, but I imagine it can jumpstart any kind of machine that runs on electricity bc nintendo logic
their secondary weapons would be something they use along with their hammers. marios is a pick (chisel) and luigis is a pair of pliers.