Is this legal?

You would be given custody of all 3 initially and you would have to contest it. Then it would be in the hands of the court. Who may give you custody of one or all of the kids. The judge may also give custody of one or all of the to another family member if they volunteer. My question is why. If something happened to their parents would you really want to split up siblings after they just lost their parents? I suggest you let her know you are no longer interested in guardianship, save the heartache of the children, and attorney fees to contest it.

Interesting question, lets consider this will as a contract. In order for it to become binding you should have some sort of compensation. Does the will spell that out. In the highly unlikely case of the death of both parents do you inherit the estate?

Even so if you feel uncomfortable about the chance of raising three children my suggestion is to talk it over with the parents.

I think the more important thing to consider is whether you're willing to parent these children. If you're not, you need to tell your friend frankly so that they can make other arrangements. It would not be fair for anyone involved if you didn't voice your concern in case this arrangement would become necessary one day.

Their will sets forth their intent and preference.

It is not legally binding on you. You can always refuse anything that someone tries to give you (or make you do) under a will by rejecting it up front. But if you accept (after their death) then you cannot change your mind later.

The "main" concern is for the welfare of the children, all of them. If you are not prepared to look out for all the children then let your friend know, so she can make other arrangments "just in case",,,,,,,,,,in my personal opinion, no children should be seperated, for whatever reason,,,,,

I think that them putting your name on their will was meaningless anyway... if they were (unfortunately) to die, it would be up to the court to decide custody (what if you were a drug addict by then?), not the deceased!

"Momma", you are on the hook, if not legally - certainly morally.

Are you a friend or not? If you can not do it, tell her now and let the woman die in peace with another more reliable and less skittish friend she can count on...

As you know, it is a major commitment..

Tough love.