On the subject of A1 and A2 Aliens; the A2 Aliens sure looked a lot more like the A1 Alien than either are compared to AVP or AVPR.
The lack of a dome in A1 and A2 was the only major difference, there were some other minor ones too, but these all may have simply been camouflage for the ridged looking surfaces surrounding them in the complex, and there are two other big theories on that too.
I completely agree with you on the A1 and A2 are descended from the same derelict genetic stock however.
Again, those difference are less than between them both combined and the AVP type.
Yes, and the AVPR aliens would then be 3rd generation. from the AVP Queen.
Juiced up Queen = G1, PredAlien-Queen G2, AVPR adults = G3. Still growing faster. At this point, "steroids being given to her" on its own is absurd.
I would agree with them having been altered, or accelerated growth at a genetic level, via increasing the amount of tandem repeats in the alien's genetic code, along the lines that would regulate the internal production of steroid hormones.
This would explain the massive size of the Queen, and the fast growth of her offspring, even beyond a tenth generation, as they would continue to pass on that new genetic sequence. That would make sense, and it would have to do with "steroids", but is just more complex than merely "giving her roids".
That being said, the AVP aliens being tampered with genetically to enhance steroid production would increase fertility (the same way taking HCG or SERMs may increase the produciton of androgens/estrogens as well as fertility), but would that genetic tampering also now make them a new subspecies?
Look at tomato plants. If someone selectively breeds a new variety, or makes a genetic alteration to one in any other way, they have made a new sub-species of tomato. Both are still tomatoes, but some will grow faster, and taste different than others due to being of different genetic stock.