Should be possible without all that much work. I probably can't get to it any time soon, though.
...i'd like a method, please, because I'm trying my damndest and can't find where targets or locations could be for any sort of interaction
Here's the outline of the technique I had in mind:
Step 1: Workshop reaction induced transformationThis is the step I'm most unclear on. An exploding rock could definitely be used, but I think I saw someone say the DFHack could be used to inflict syndromes in response to reactions and was much more reliable than exploding rocks.
The target creature should be transformed into the unit type we want to spawn. The transformation should last for ~10 ticks or so.
Step 2: Transformation induced pregnancyDFHack should induce pregnancy in response to the transformation beginning. The
truetransformation plugin responds to syndromes beginning, and can probably be adapted. The
Catsplosion plugin demonstrates how to induce pregnancies with DFHack. The pregnancy should be set to finish in one tick.
So, to summarize, the pregnancy induction code from catsplosion should be hooked into the syndrome response code from truetransformation.
If all goes as planed, the dwarf completing the reaction will transform into the target creature type, give birth 1-2 ticks later, and then turn back into a dwarf after a total of 10 ticks or so.
I just hope that syndrome-transformed creatures give birth, and give birth as their transformed unit type and not as their true unit type.