Yes you should try this EEPROM through xblast and see if it unlocks. the HDD key should be the same for both the 200GB and 10GB HDDs so long as they where used in the same xbox. at worst it would just fail to unlock so it will not damage any data.
if it doesn't unlock it should still have a chance of pulling the EEPROM from the board with a raspberry PI. so long as the board is powered up you can still recover it this way.
https://consolemods.org/wiki/Xbox:PiPROM
as for the new drive Error there is a lot of parts that could be the issue.
What Bios are you using?
What is the Error Code?
how are you trying to initialise the HDD?