> Do these "studies" account for second-order effects on housing, local job markets, etc.?

Yes everything improves. Displaced workers find new jobs, markets and economies expand, etc. etc.

> At the expense of legal immigrants who bothered to do it the right way.

This is just nonsense, immigration isn't a zero-sum game.

> Some of these studies exist for legal immigrants, cite the one making this case for illegals?

Google it, I'm at work

edit: had a lull, here you go https://www.epi.org/publication/unauthorized-immigrants/

The money quote:

> If we examine just the net fiscal impact of unauthorized immigrants, even this is positive, despite the fact that lacking work authorization also means being trapped in low-wage work and being unable to adequately assert one’s labor and employment rights. A prime reason the net contribution is, nonetheless, positive is that many unauthorized immigrants pay income taxes and have Social Security taxes withheld yet are generally ineligible for government benefits and services.