Agents of SHIELD (SPOILERS)

[ZeroBG82]

I'm wondering how Deke got access to virtual Coulson. May said they saved his hard drive... I can certainly buy that his "memory" was being backed up frequently or in real time to a hard drive, but that hard drive had to be on the Zephyr, and therefore inaccessible to Deke and Mack in 1982-83.

The same way Sybil salvaged her Time-stream viewing doodad. By going directly to the source and salvaging it from Coulson's ruined robo-corpse after the explosion. In control of the lighthouse, Deke would have had direct access to the blast sight.

Also, why did Sibyl build some half-assed hunter robots out of spare parts when she could have gone back a few minutes before Coulson blew up the ship and either a) stopped him or b) jumped forward to fight SHIELD in 1983?

Coulson destroyed the Chronicom's ship. And with it, presumably their ability to move through time. Sybil is stuck in the 80's same as Deke and Mack, prior to the Zephyr's return. Or at the very least, because she had lost her Time Stream reader, and could no longer safely predict what any changes she might make would do to the timeline moving forward. Now she has her Time Reader so she can predict the future and make changes again. But she appears to still be stuck going to the long way round.