I have the drive new and have been using it continuously for 3 days. I'm delighted, it only gets lukewarm, is very quiet and the speed is very good for an HD. Housing is top notch. The HD can certainly be replaced. (Even if I haven't tried it yet 😁) The aluminium housing can be unscrewed so that a defective hard drive can be replaced. (I have already done this with several external HDDs)
The disc is really recommended.
No, the hard drive has a (1x) USB-C connector that can transmit USB 3.1. Even though Thunderbolt 3 uses the same connectors, it is a different signal that is not compatible with each other.