Does these characters include Supes?
I think so. Others may feel he should be completely transcendent of Earth, but especially in his early outings, a nuke should be like a bullet for a normal person. It'll probably kill him. It might not, if he's lucky (and he will be lucky), and it won't vaporize him, but he can't shrug off everything humanity can throw at him physically, which keeps with the theme of him being profoundly affected emotionally by humanity.
Hypothetically should this new movie superman be strong enough to take on all the mcu avengers at once?
I think so. This has been true of every live action version of Superman, including the mopey teenaged version. I see no reason to change that now.
Well using the argument people are giving of how thor and hulk had to be tamed power wise as to not make the avengers team irrelevant, i wonder what dc would do in a similar situation with superman in a jl film?
Especially if they want to use this superman?
I like your questions. I say: no, don't tone him down. A JL film that brings together characters from solo films should be off the charts. Let all the characters be at the top of their game. Superman is more powerful than just about everything on the planet. Batman is clever-er than everyone else on the planet. Then turn those into problems for the rest of the team. The scale has to be bigger, because Superman could clean out New York solo, so you have to have a threat that truly is world-sized... but it can be done, and perhaps even affordably with clever writing.
Or you can tone their powers down and do it like Avengers.
That's ridiculously powerful. He could literally make earth his personal treadmill. I really don't see the point of making him THAT strong. In the same comic it is also mentioned that he can toss the moon out of orbit. Seriously!? I love Superman being really powerful, but that's crossing the line and taking a s*** on it. The only thing more powerful than that is his ego. What next, Superman and Zod fly into space and use planets like a snowball fight? It's funny yet it's sad.
This. When you make your character obscenely powerful, specifically, when they become more powerful than anything on Earth, you remove not only a vast number of physical conflicts as possibilities, but you also remove all the relatable instantly identifiable physical conflicts, and limit your stories to only fantastical extra terrestrial conflicts on a scale that is hard to visualize, and hard to visualize compellingly.
There's a reason DBZ is a soap opera, because without a LOT of emotions tied, blowing up a planet looks 'funny, but sad' and even can be read as projecting confidence issues, like that kid who played superheroes but always wanted 'gravity powers' or some obscene one-hit thing. It makes Superman look like a power gamer... unless you load him down with soap opera (as DBZ does, as Supe did in the silver age) or take him down to the level where there are people, perhaps not many, but a few on the planet who can hurt him. Your Lex Luthors, your Metallos, your Parasites.
Meh, I'm ranting now.