@Ronoko
There are two problems:
The author distributes these models through a paid subscription. I don't charge people for these models, but I don't intend to spend my own money on them either. "You can have access and also ask me for other models or skins through Subscription"
The author also states: "The use or conversion of my models on any other platform is prohibited." So even if I obtained the model legally, I still wouldn't be allowed to convert or use it for my project. In practice, that means the model has no future there because its use is restricted by the author's terms.