From Oxnard at midnight local time on 22 March 1957 (23/0800 GMT) the bright star Vega (mag 0.0) would have been 15deg 20min alt 53deg 14min az, i.e about right where the main visual witness saw her "green light". See the reconstructed witness drawing in the file. The light rose steeply at slight angle towards her right (S), initially in an apparent zig-zag but mostly straight, attaining several times its initial elevation during the course of several hours. This track as drawn is very close to the position and angle of the track followed by Vega as it rose at around 10deg/hr.
The light was mostly "round", angular size compared inconsistently to different-sized coins at arm's length (fairly typical overestimate of a bright star), but at one point when low down appeared elongated laterally, with vertical spikes or beams appearing. These details might be explainable by mist at the top of a local inversion, for example, and/or diffraction effects in the eye. The green colour could also be a propagation effect, and/or a colour contrast illusion caused by comparison with the reported nearby red lights.
The two red lights were below the horizon and off to the left. The AF report notes the presence of red-lighted masts. She said she saw these two lights take off rapidly later in the end of the sighting, but I don't have a lot of faith in this. There were two F-89s being vectored unsuccesfully around looking for the UFOs. Maybe she saw these? She was described as "hysterical" in her initial report and "excitable" and during interview.
There seem to have been lots of other sightings of lights by police and others, possibly triggered by this report, but oddly they mostly describe red lights, or a white object with a red light. I don't see any reference to other green objects, and no evidence that these witnesses were seeing the same thing. Jupiter was bright (mag -1.3) high in the SW. Descriptions of high-speed motion all seem to refer to small jitters inside a small angular area. The duration of hours and everything else seems to add up to "astronomical".
Nothing;'s very certain, but in my opinion (at the moment, based on what I've seen) the Oxnard sightings and the radar incident were probably just coincidental, and the latter was an electronic glitch