As for Edison, he'll wield a beam sword (apparently Nintendo can't say lightsaber), because it seems like the obvious, natural progression for the guy's most famous "invention," the light bulb. Continuing with the light theme, he'll also be able to throw shurikens made of pure energy -- the perfect weapon for swiftly electrocuting dozens of stray animals, as Edison once did as part of his anti-Tesla smear campaign.
Perhaps not with this exact method, though I'm not discounting it.
Note: I have no input whatsoever in these fights. I've simply set up the fighters as Level 9 AI-controlled bots and let them duke it out by themselves. It is the scientific thing to do.
Only seconds into the fight, it becomes clear that Edison is that guy: the one you can't hit at all because he uses blade counter (a move that returns any damage you try to inflict) over and over. Basically, he's letting Tesla do all the work for him again.
As Edison once said, "Genius is 1 percent inspiration, 99 percent [others'] perspiration."
The Edison AI player also proved to be disturbingly accurate in another way: motherfucker plays dirty. The famous incident where he offered Tesla $50,000 for a job and then said it was a joke when Tesla finished is represented here as a series of direct punches to the dick.
This is literally the reason Tesla never had children.
As for Tesla's arm cannon: it's pretty and energy-efficient, but mostly impractical. Much like a Tesla car.