An L-2 spouse is employment-authorized incident to status, so she may work for the U.S. outfit or anyone else once admitted. That is a real difference from TD, but it does not mean she can do the work before her own L-2 admission is granted.
L-2 spouses may work; the timing and the status still matter
Spouses of L-1 transferees are admitted in L-2 status and, under current USCIS policy, are considered employment-authorized incident to that status, with the admission record itself serving as evidence of authorization for a period. That means the spouse may be hired by the U.S. custom-harvest company as a bookkeeper, dispatcher or anything else, or may run her own business.
Three cautions apply. First, she must actually be admitted in L-2 status; entering as a visitor and starting work is a violation. Second, if the household plan is that she will be the one who really runs the U.S.
outfit while the transferee is in the cab, the petition is describing the wrong principal. Third, unmarried children under 21 in L-2 status may study but are not employment-authorized, and a child who turns 21 must have a route of his own. Ask the employer for a written offer for the spouse only after her status is confirmed.