When checking 'Copy Financial Properties and Financial Plans' option, this overrides the template and the template cost plan is ignored.
When you convert an idea and want to use a cost plan associated with a project template, the 'Copy Financial Properties and Financial Plans' option would need to be unchecked when doing the conversion.
If you check the option 'Copy Financial Properties and Financial Plans' this will copy the plan associated with the specific idea and not look at the template. Therefore, if your idea has no cost plan and you check the option, no cost plans will be created on the project. The .