L-2 spouses are employment-authorized incident to status and may work for any employer. Whether he can work as an electrician also depends on state or local licensing for that trade, which is a separate question from immigration permission.
Permission to work is not a licence to practise
A spouse admitted in L-2 status is authorized to work without applying for a separate employment document; the admission record itself serves as evidence, though many spouses still obtain a card for convenience with employers. That permission is general and is not tied to the L-1A company, so he could work for the subsidiary, a competitor or anyone else. The trade itself is regulated separately.
Electrical work in most U.S. jurisdictions requires a state or municipal licence, and reciprocity with a Saskatchewan journeyman certificate varies from place to place. Ask the subsidiary's local electrical contractor or the state licensing board what an out-of-country journeyman must do before pulling permits.
Children in L-2 status may attend school but may not work, and they lose L-2 eligibility at 21. Plan the family's arrival so that his licensing application can start as soon as he has a U.S. address.
Hypothetical example: The founder's spouse wants to earn income by operating a mobile bicycle-fitting studio after arrival. The family should first confirm that the admission record identifies the spouse in the classification that carries work permission, then ask the relevant local regulator whether any business registration, tax account or occupational rule applies. The admission record settles immigration work authorization; it does not settle the local rule.
A first review produces a separate start-up checklist for the spouse and a school-and-age timeline for the children. Waiting until a child approaches 21 leaves less time to choose another lawful status.