Yes, some games can run from external HDDs.
Yes, some games can run from external HDDs.
USB 2.0 offered around 480 Mbit/s, but real-world performance was often lower due to overhead, which is why I usually treat it as about 30 MB/s at best. That’s still insufficient, though. USB 3.0 delivers speeds of 5 Gbit/s or more (plus 10 and 20 Gbit/s variants). Even with the overhead, which is now minimal, you’d still exceed 300 MB/s—far beyond what any hard drive I know can handle. I doubt you’ll encounter a bottleneck there for this reason.
Varies by device, storage, controller, etc. It generally falls within that range, though I've rarely observed anything consistently over 30 seconds enough to confirm it wasn't a coincidence.