My wife and I are in the process of establishing who should be the guardian of our minor children and who should be the trustee for the children's trust. Our inclination is to have my wife's sister be the former and my brother be the latter. How important is it that those two individuals cooperate while our children are minors? The trustee is directed to pay for the health, education, maintenance and support of our children, but I presume the guardian would typically have some ability to request funds. What happens if those two people disagree? Our concern is that these two people have different values and morals and haven't been very friendly towards each other in the past.