FOSS gamedev and creative worlds

Would it be possible (and legal) to make a mob set out of this?

https://rymdnisse.net/downloads/minecra ... r-rig.html

Possible? Certainly.
Legal? I wouldn't touch it with a 10 foot pole.

Its written below the page
https://rymdnisse.net/downloads/minecra ... g/faq.html

Copyrights? What can I use the rig for?

You are allowed to use the rig in any video/image/comerical.
You are allowed to sell and make a profit of the videos/images/comericals created with this rig.
You are allowed to monotize your youtube videos and make a profit from the videos using this rig.
You are not allowed to give out this rig for download somewhere else or claim it as yours.

Do I have to give credits if using this rig?

Giving credits is totally up to you. If you don't want to do it, then I won't force you.
Credits are always really apprechiated though! :)

First of all, that's not a really good license, it sucks (from a FLOSS point of view).

Second, this is basically a rip-off of the models and art made by Mojang. Best you can do is claim fair-use, but that's border line and can backfire.

What would be needed to make a mod out of this? You are not allowed to offer these models or textures with your mod, you'll have to provide a script that downloads them on the fly. Then the license does not state what the situation is regarding modifications, so if in doubt you have to assume that these are off-limits, so not allowed to be modified (this is further confirmed by the limitation that you are not allowed to offer these for download).

The most important limitation is the fact that it is only a rip-off of Mojang property, so even if put under a free license, even touching it with a 10-foot pole might be problematic.

I know that within the Minecraft community a "sure, do what you want with it" mentality has developed (fueled by Mojang itself since they never provided a mod API and their policy was for years "you can decompile and change the sources, that's cool...oh, don't mind what the EULA/License says"). But this mentality is absolute poisonous for FLOSS and a "promise not to sue" has absolute no legal binding. If in doubt, touch nothing that comes from the Minecraft community, that includes code and artwork, unless it is definitely licensed under a free license, licensed by the original author and is an original creation.