Fact is CG never went with any consistency on ships. These "missing droids" on many of the ships could have been easily fixed had they went with the ship hardware option, originally. Then each ship showing a droid could have gotten said droid without it being a playable toon.
Then it was dropped.
Now we have a lot of ships needing droids to make sense - but no chance of it happening. And the two droids we do have aren't attached to any (R2 could easily be part of the millennium falcon too). The 1, chopper, stands out as the only one that makes any sense, though since it's just him.... does it?
TL:DR; Ships were never implemented right, and continue to be released with any consistency.
(this has nothing to do with whether you like ship battles or not, I do, but that doesn't make stuff liek this cringeworthy)