External drives on USB hub
Solution 1:
I think that connecting them both directly would be the best solution, but you might get away with connecting one to the hub.
Assuming that the limitation on read/write speed on the drives is the USB bandwidth, connecting them both to the hub would limit both of them to the single 480 Mbps limit of USB 2. Since your mouse and keyboard are low-bandwidth devices, their presence on the hub should not significantly affect transfer speeds.