Can anyone tell me if I download daz3d models for free from this forum, and use models in a 3d game in Unity where the models move, will I have problems with licenses?
Well, to start off with, by downloading the daz3d models from this place or any other place, you're already using the models without a license, regardless of whether you're using them for 2D or 3D. Basically, if you haven't paid for them, you don't have legal rights to use them in any way whatsoever.
If you
did buy them, then you have the right to make 2D images from them, but not to embed the model in a program. For that, you need the interactive license, over and above the purchase of a "standard" license. (Assuming that the asset
has an interactive license - not all do. An asset that doesn't offer a 3D license can't be legally embedded in a program at all, because the standard Daz license does not grant that right.)