I'm NOT an attorney and CAN'T provide legal advise either but as i understand it, a will is basically a set of instructions for the court to use after your death if your estate requires a probate.
The trust can avoid probate and is typically private compared to a probate. A will is part of a trust.
You can also have just a will, but it will not avoid probate on it's own..
To my limited knowledge, you can't name minors in a gun trust as succesor trustees because they can't own them. You might be able to name guardians for the minors until they come of age
No matter what, do your homework...good attorneys are worth their money over the long haul imo
Hopefully some of our licensed legal shooting friends will chime in to provide some good advice