Is it permissible to establish a Roth for a child under 18?

Would this be a custodial held Roth account?

If allowable, is the family income a limiting factor like it is for the spouses to have Roth’s or are the children under their own income limits?

Does a “reasonable” test allow us to prove that the child earned income via chores (vs a W2 or 1099)?
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