I don't think it's a copyright issue, but between the colors, illustrations (some of which almost match exactly), and the appearance of the widgets, you could make a very strong case for trademark/trade dress violation.
Trademark and trade dress have nothing to do with a DMCA takedown though.
And besides, establishing an infringement of trademark and that it was then infringed will require an absolute mountain of cash and lawyers and time. I'm assuming they have nothing relating to the IP they're annoyed about on paper and so they'd need to show that they 'owned' it in equity. They'd almost certainly go bankrupt before they have a chance of winning a case in court.
> I don't think it's a copyright issue, but between the colors
The only thing you can file a DMCA takedown notice for is a copyright issue. That's it. By filing a DMCA takedown notice you are asserting there is a 'copyright issue'.