Not because of the shareholding. A spouse who accompanies the investor in qualifying E dependent status is generally employment-authorized incident to that status, with proof such as an E-2S notation on the I-94 admission record. Alternatively, a spouse who is a Canadian citizen may have an independent case worth assessing on its own facts.
Decide each adult's route before the shares are fixed
Discuss shares, control, and duties before finalizing the restructuring. A co-owning spouse may still seek derivative status if eligible; shares alone do not dictate the route. Family applications have their own requirements and may remain dependent on the principal, without a guaranteed common date.
E status for an unmarried child under 21 confers no work permission; from 21, another basis for stay needs examination. Hypothetical example: a hardscape and permeable paving contractor is owned equally by two spouses, and the restructuring plan gives one of them all the shares of the United States company so that the ownership reads cleanly. That change may simplify the treaty-nationality analysis, and it also takes something away from the other spouse; both effects are real and should be weighed together with tax and matrimonial advice rather than on the immigration point alone.
Ask what each adult intends to do in the United States, then ask which route supports it. Where one spouse expects to hold a role in the business, describe the role and have it assessed against the status that spouse will actually hold, since the shareholding does not settle that question.