There are a lot of rules for LEGO Ideas: https://ideas.lego.com/guidelines#content You might want to investigate further before you get too far invested.
Including, “Focus on a single concept or license.
Your project must focus on a single concept, similar to our own sets that feature a main model and a few smaller supporting models. For example:
Don’t attempt to pack an entire playtheme of models into a single project.
We don’t accept “mass customization” projects such as custom mosaic or minifigure makers.
Only reference one third-party property per project. For example, we wouldn’t accept a project containing both Porsche and Ferrari vehicles.”
You can certainly still work on the project, but submitting it to LEGO Ideas is another matter entirely.