Gun shop name, google search, friend's name, etc.
If no spouse type N/A
If no Spouse just type in N/A
Naming a child does not make them a trustee or beneficiary and does not mean that they will have to go through a background check.
The default name is [Your Name] Gun Trust, but you can call it anything you like. Keeping it short is a good idea if you ever plan to make your own SBR or Suppressor. Some folks like Armory or Firearm instead of Gun.
A successor trustee has no right to possess the trust property during your life. They only run the trust if you die or lose capacity.
You aren't required to have more than one Successor Trustee, but it's a good idea to have a backup if the First Successor can't do the job.
A remainder beneficiary is the person who will receive the property from the trust after your death. A person named as a Remainder Beneficiary does not have to go through a background check.
It can be 100% or something less than that. The total of all remainder beneficiary shares must total 100%.