Practical questions can be identified early, while the principal’s eligibility and each person’s status remain subject to assessment.
Keep the permissions individual
Qualifying L spouses are employment authorized incident to status with appropriate documentation. Children do not gain work permission solely through L dependent status. Do not treat a proposed employment calculation as approval of the household’s move or activities.
Work out which party actually confers each permission, because households routinely attribute all of them to the petitioner. The employer petitions for the principal and for nothing else. A qualifying L spouse's employment authorization arises incident to status with appropriate documentation, which is a matter of that spouse's own status rather than of the employer's letter, and children in dependent status gain no work permission from it at all.
Nobody in the household should give notice, accept an offer or enrol in something that presumes a permission until the document evidencing it exists. Hypothetical example: a spouse who runs a small tree-care operation should not commit to U.S. clients on the strength of the principal's pending petition, since that petition speaks to the principal's transfer and says nothing about her authority to work.
Ask which document each person will hold, and what each of those documents does and does not allow.