Hi! Card Duel System does take inspiration from games like Forbidden Memories in some ideas, but we are not directly copying its assets, content, rules or implementation.
CDS has its own systems, mechanics and workflow, with a much stronger focus on customization. You have control over many parts of how the card game works, and the Expansion Packs keep adding new mechanics and possibilities beyond the base system.
We also strongly encourage users to create their own card designs, artwork, resources and visual identity. The idea behind CDS is to give you a flexible framework to build your own card game, rather than reproduce an existing one.
So in that sense, you shouldn't have any particular issue just because some of the inspiration is recognizable, especially if your own game uses original or properly licensed assets, names, characters and branding.
Regarding VisuStella, CDS is mostly self-contained and does not replace RPG Maker MZ's normal battle system, which usually helps it coexist with other plugins. Of course, with a large plugin ecosystem there can always be specific combinations that behave differently.
You're very welcome to try CDS with your current setup, and if you run into any compatibility issue, we'll be happy to look into it with you and work together to find a solution whenever possible from our side.
Our goal is for CDS to be flexible enough to fit into different projects while giving developers the freedom to make the card game truly their own. :)