Never let a good crisis go to waste!!
Just kidding, but that is what Rahm Emmanuel says. I all seriousness I see no problem with discussing the issues and advantages of homeschooling with public school parents. That's not "evangelizing" per se, though it can have a similar effect.
As far as taking in "stranded" kids for
profit purposes, while I'm in favor of entrepreneurial solutions, in most states the regulations surrounding day cares, private schools, homeschool co-ops, etc can make doing that potentially a mine field of legal problems. Helping those parents set up their own thing is probably fine, but suddenly having half a dozen, never mind 20+ kids showing up at your place to learn and/or be cared for while the parents go to work is where you'll get into trouble.