Oh I’m quite happy with the solution. Only drawback is that the customer has to type a “©” when he wants to put copyright information, but I think that shouldn’t be a big deal 😉 .
The code above is more like copy pasted from here and there, fiddling around and see what happens, but when i reach a point at which I know there is no better way than standard wordpress/ACF solutions I am mostly happy with that because I know it is the best possible solution, and … I learned a little, maybe it helps in other situations in future 😉