I am not a law experts. But here are my views of your concerns.
Not able to own land : If someone already own lands, the ownership may not cancel after getting another country citizenship. If so buy some lands and then apply for the citizenship. In wider view, new lands from SL may need for their next generation. Not for them. That is also depend on their kids future vision. If kids hardly need, they will pay said 200% tax easily & buy lands. Because SL will not develop/change for another 2-3 generations & foreign currency rate may not come down. . So as summery they don`t need to worry about this at the moment.
Government health services will be not free : Though is it free in some points, how many of us going to O.P.D ? Mostly consult a doctor and getting treatments for minor cases & some people have ability to pay for special cases like surgeries too. If your relations return to SL in future, they will bring some considerable amount of money. So they can pay and get medicine from any private hospital without any issue. Isn't ?
Government education not free : This is possible to apply for their kids. Send them to a private/international schools if they return to SL in the future.