Yes you can develop projects with CE version and need to change some packages if you move it to Enterprise edition because in Enterprise you won’t get all latest package you used in community edition.
Yes, It contains REFramework template.
Yes, If both are using same version then you can move your code. And if it is different version then there will be chance to change used packages.
Thanks for you reply. I am aware of differences between the CE and enterprise package version and that´s fine. But my question was more about legal point of view.
Legal point of view in the sense ?
Here, you are developing the code right. So, you have the rights to sell your product to other clients. It is illegal if someone developed code and you are trying to sell.