A: No, the Hologram can only be one Keeper at a time. It’s already a very powerful card – if it could be any TWO Keepers at once, it would be ridiculously overpowered. Now, it is possible, when combining certain Star Trek Fluxxen, for there to be TWO Hologram analogues in the game (Holodeck/Holosuite.) So, if a player has two, one of them could imitate one Keeper owned by another player, and the other could imitate a second Keeper owned by another player.
It is possible to win with one Holographic Projector even if you don’t have either of the required cards yourself only if the win conditions include a Creeper or Creepers which are attached to a single Keeper owned by another player. In that case, the Holographic Projector only needs to be one Keeper, but it also mimics the associated Creeper properties. A few examples of Goals for this type of win would include Imperial Destroyer, Evil Computer, Evil Brain Parasites, Robot Uprising, The Power Of Evil, and Malfunctioning Transporter.
See also: Can the Holodeck count as both itself AND someone else’s Keeper…