I think it is a good plan. You will have to get the i7 and put or buy 32gb of ram for video / 3D.
But, since you don't have a monitor, you might want to think about the iMac. With the mini, you will have to add an eGPU to the mac mini for 3D modeling and larger video editing projects. I like the idea of the eGPU because they are upgradeable (just dont get the black magic version, you cannot upgrade it) so in a few years you can change the card if you want.
BUT, since it sounds like you dont have a monitor, the price of the eGPU and a monitor might be too much?