I can't say that your safe since there is an obvious similarity to the other brand. If they want to cause problems, they probably can. Before you keep investing money, you should consult an attorney.
I tend to disagree with this. First off, blank garments cannot be protected (unless there is something special about the garment that qualifies it for a patent). So that should not be an issue at all. Second, t-shirt designs typically come and go. Each season, companies launch new designs and the old ones are discontinued. Yet the brand name lasts forever. So if there is a priority in terms of IP protection, it is generally the brand name, not the individual designs. Don't get me wrong, if there is blatant infringement, companies will pursue legal action. But oftentimes concepts and ideas can be ripped off, but the design itself is different enough that it's not infringement. That's why you see so many similar design concepts out there. For instance, I can launch a brand with designs based on the SoCal lifestyle, but I certainly cannot call it Hollister (or any similar variation).More importantly I think is that you are not doing the same things as Rook,,, don't copy their blank items, and hopefully your art does not look like their art.. I think that is more important than the name...
Ideas cannot be protected as intellectual property. Products are protected by patent. Brand names are protected by trademark. It is possible for multiple trademark registrations for the same name if they are for different classifications. But when there are two similar marks in the same classification, that's when companies get lawyered up.There are a lot of companies out there with the same names and no one gets lawyered up until someone is plagurizing someone elses ideas and products