If there is an official/confirmed canon explanation, i'd love to hear it, but right now, i'm going off my own blatherings and head-canon.
So, it's obvious the queen could've, in high likelyhood, snatched one or two eggs on her escape out of the hive and made her way to the the sulaco, had the fight and got blasted out, but had zero chance of sneaking into the cryo bay and spending ample time to hide it, Let alone two eggs without explanation to infect both ripley and the dog/ox, meaning they would've been sucked out with her. Had any xenos stuck on with her, the fight would've gone vastly different.
I'm also inclined to believe that the idea would be that a Royal facehugger has the ability for secreting both a queen embryo and standard worker/warrior embryo; a kickstarter hive for xenos, basically. Hence why we see it dead after infecting the ox.
Regarding the implication of Bishop; His sole purpose, being a WY company android, especially under Burke's orders, were to bring a specimen back; Burke obviously tries his hand at subtlety, trying to infect both newt and ripley in the med-lab. Bishop, having levels of empathy towards humans (Not to mention his behavioural inhibitor), as well as being coded to follow company commands and protocol, wouldn't be able to do such a thing, but has no objections for being indirectly responsible for the impregnation of anyone, all he's doing is stealing an egg....right? He would at least would have the highest likelihood in both finding and secreting away an egg.
The only issue with this is that eggs are easily disturbed and/or have a varying hatch time, not to mention having to go into the hive himself in order to grab one....in front of the still living, still birthing queen and her brood of workers.
This also raises another question; would a xeno egg hatch at the presence of an android which can't support the gestation process? For the sake of my point, let's say no, based on xenomorphs being able to pick up human pheromones, or the fact he came in of his own accord, willingly and unarmed.
The only viable timeframe for this incident, anyway, if Bishop managed to actually do that, is him remote calling and flying the dropship before Ripley and Co meet him, meaning he would have to call down the dropship, fly over to either the atmo plant or the derelict for the egg, go back into orbit, plant it then come back down. All of that, within the alleged 15 minute timeframe he gave to Hicks while they were escaping the control centre through the vents. Another question; Can androids lie?
Back on the point of the facehugger, Bishop grabbing a particular egg, especially anything like a royal egg, would be astronomically lucky. So it comes down to xenomorphs having hivemind and telepathic abilities, with the Facehugger either knowing about the queen's death or destruction of the hive or being conscious enough to know it's nowhere near home (on the sulaco) and began morphing into a Royal for the sake of survival.
