No. Implementing the procedure, training staff and signing releases is productive work that requires L-1 status; it cannot be done on visitor entries while the petition is pending. Short visits to observe the site, attend meetings or scope the gap are visitor activities, but the line is crossed when she begins doing the job.
Use the pending period for scoping, not implementation
The pressure from the acquired site is real, and the temptation is to have the specialist 'consult remotely and visit occasionally' until approval. Draw the line carefully. From Quinte West she may continue her Canadian role, including advising colleagues at the US site by phone or video, since that is work performed in Canada for her Canadian employer.
On a visit to the United States she may attend planning meetings, tour the facility and take notes for the implementation plan. She may not run an investigation, sign a release, deliver training or configure the site's systems until admitted in L-1B status. Plan the timeline backwards from the milestone at which the site must operate the procedure: file Form I-129 as soon as the evidence is assembled, consider premium processing if the milestone is close, and once approved she presents the approval notice at the port of entry as a Canadian citizen.
If the milestone cannot wait, the company should consider a local interim measure rather than an improper early start.