Yes. The spouse of an E-2 investor is employment-authorized incident to status and may work for the business or any other employer. Children under 21 may study but may not work.
The spouse's work permission is broad; the children's is nil
Hypothetical example: the buyer's spouse is a bookkeeper and intends to run the company's office, and their 17-year-old wants to apprentice alongside the plumbers in the summer. The spouse may work for the company or take outside employment once admitted in E-2 spouse status; the annotated I-94 serves as evidence of authorization. Paying the spouse a wage is ordinary, but keep records tidy because the business's payroll is part of the evidence for non-marginality. The 17-year-old cannot be employed by the company or anyone else while in E-2 dependant status; unpaid shadowing that displaces paid work is also unwise. When the child turns 21 the dependant status ends, and if they want to stay they will need their own status, such as a student visa. Plan the family's admissions together and keep passports valid well past the intended stay, since E-2 visa validity and admission periods are limited by the passport.
Hypothetical example: the buyer of a small brewery-equipment service company plans to bring a spouse who will handle marketing and a 20-year-old child who hopes to do paid weekend work. The family must decide roles before travel: a qualifying spouse may work after proper E-2 dependent admission, while a child in dependent status may not take employment. An opening file audit should assemble a payroll plan that does not rely on the child and a separate education or immigration plan for the child after turning 21. Relationship records settle derivative eligibility; a place on a business website does not. Trouble develops when the business plan counts unpaid family work as a substitute for needed hires or when the family assumes a dependant's status continues automatically after the age limit.