IMO it should be the bloodstone. Zemo's an awesome villain and The Bloodstone Hunt is the storyline to use.
Wasn't the Bloodstone literally Ulysses Bloodstone's skeleton?
I think the time stone is already in GOTG. why not the reality or soul ones? One can be in doctor strange and the other in cap 3. I say the soul gem in doctor strange and the reality gem in cap 3 with Zemo and Crossbones as the villains.
No thanks. They should keep Cap grounded and on the more "realistic" side of the MCU, not to mention it doesn't make much sense for it to have the final stone since it's at the beginning of phase 3. Leave the stones for the Doctor Strange's, Thors, Inhumans, and GOTGs of the world where they belong.