Alternatively, if I created a large body of works that were 90% Lisa Frank and brought it to a large market distribution, making significant revenue, then she could sue me for damaging her market and her brand. Which she has done to others in the past and rightly won. Go Lisa Frank!
But, if I used an AI tool in the process of making an image that came out 10% Lisa Frank, she wouldn't have a strong case against me. Nor does she have a case against the million random teenagers hand-copying her style but not making significant revenue from their copies.
Either way, AI doesn't really factor in here. The results are the results and the markets are the markets regardless of AI or paint brushes.