sometimes I wonder if this lifestyle is good for them or possibly harmful, I don't know 
yes you do .... think it through...
you have wonderful, mature children who have direct experience of the biggest fact of life of all (death) and who are resiliant enough to accept it when it happens ... and get back to normal childhood things like playing.
And I've heard enough about their choices of friends & acceptance of different cultures to know that they will be the peace-makers of the future, rather than the narrow minded rule makers that their peers may be.
(enough eulogising woman, there's things to be done!!)