It might be important to differentiate if these new dwarfs are in the first two migrant waves and what other civilians in the home civ have for skills.
It is known the first two migrant waves will be auto-generated when the civ is nearly dead, but is it known if the code is used when the home civ has dwarfs to send?
And if there is a non-dwarf in the home civ's military with the pike skill, are they a source of pike skill training for dwarfs migrating from that civ?
Not quite what was asked, but unless the civ is truly dead according to DF, void dorfs will be generated as needed for every migrant wave, including those beyond the two first ones.
Which trend are you seeing for near-dead civ auto-generated dwarves in 47.04? Lots of legendaries, or bunches of completely skilless peasants? So weird how both trends are being reported at the moment. Must be something to do with the kinds of worlds people tend to play in.
I've never seen a skilless peasant arrive in any version of the game so far except through becoming an adult. "Peasant" normally indicates a skilled fighter who needs to be in a squad asap.
And if there is a non-dwarf in the home civ's military with the pike skill, are they a source of pike skill training for dwarfs migrating from that civ?
The current hypothesis is that the fairly common foreign weapon skills being seen in 47.x are being picked up while fighting with mercenary groups (who can specialise in weapons beyond each civ's restrictions).
With the amount of fighting going on in the world in 47.x this seems fairly reasonable but needs Science.
Humans with pike skills living with dwarves have been a thing for many years, so probably unrelated.