^9
1 - Maybe. You're also removing them from the economy and their demand for products/services as well, so a decrease in employment overall is also likely.
2 - They're not statistically more likely to engage in criminal activity than any Citizen is, so your total crime numbers might decrease (just like can be anticipated with any pop drop), but it won't be any different than we would see if we just eliminated a segment of the Citizen population.
3 - Yes.
4 - Not likely to be noticed. Illegals do not personally qualify for most welfare services, only a few. And the cost per illegal headed houshold in services is like a net $3k per year - less than for Citizens with similar economic situations.
5 - Probably for providers, but I doubt your premium will go down anytime soon.
6 - Depends. By decreasing your tax base you might actually increase your personal contribution to education. Fewer students wont always mean decreased cost to you personally even though the net cost will drop.
7 - Unlikely. Insurance isn't really paying that much for them now, service providers are the ones bearing the brunt of this.
8 - Probably in some markets, but construction cost will likely rise. So some decreases, some increases.
9 - Depends on the area, but generally yes.
10 - Um, I guess kinda. Though query how global pollution might be impacted.
11 - Same as 10.
12 - Same as 10.
Legalizing about 10 Million of them would probably be more beneficial than deporting 28 million of them, just my take on it.