Have you tested these yet
@
Matt Helm
?
I just wonder how they play & whether they actually feel like the turtles? I think there is a reason why nearly all custom designers on the site have made them separate heroes. But if you are happy with them as a squad then all good. I personally like them as heroes with their own individual personalities & fighting styles. But also more than 1 life each.
As for designing a card. I will see what I can do with the free software I have downloaded now that my computer is behaving. I found Krita to be very similar to Photoshop.