If I understand how genMissionRaceFromAlienBase: and huntMissionRaceFromAlienBase: work they override the assignment of a UFO's crew so that instead of being from the base launching them it uses the raceWeights: settings in the related alienMissions: entry.
What I suggest is that a true / false variable is added to alienDeployments: that is similar to those two except that it causes the UFO to be assigned the race matching the alienDeployments: race: or randomRace: variable's result while it is on the Geoscape so that the Hyper-wave Decoder / Transmission Resolver can accurately list the race crewing that UFO.
To give an example of why that could be useful I've been trying to code a mod that makes use of randomRace: to cause all UFOs in the same wave to randomize their crews. However as a result the Hyper-wave Decoder no longer will produce accurate results. To alleviate this inaccuracy I've been trying to use placeholder races that represent the range of what could spawn. Unfortunately the negative of this is that the worth of building the Hyper-wave Decoder is reduced for the player which was not my intent.