I know a common rule of thumb in other games aims for finding two points of contact to determine if an IP has been breached. Obviously certain names like Spider-Man or Batman would be notable rips on existing IPs even before looking at the costume, but so long as Arachnid-Guy and Batdude have their own unique take on the costume, they'd fall more under parody or homage. As for the Marvels, we've been using the name for a long time now, even before we were hosting CC's. We've never copied a single IP from Marvel, nor do we claim that we are Marvel. We used a word in the English language that has obvious throwbacks to the company because we're fans, as can be seen in how most of our winners were more tights-based heroes. Unfortunately, Marvel is now using that same name for their IPs. Clearly, we don't want to lose the name, but if the GMs determine it's against TOS, then we'll have to suck it up and accept a new name.
It's just more than a little strange that we haven't hosted a CC for months and haven't been public much at all recently and yet we're 'bending the rules', have preferential treatment and other nonsense though.
As to the original discussion, UltraAlt's suggestion is likely your best bet. Do what you can to mimic the aesthetics and tone while making it your own and you should be safe from Impervium 🙂