Nobody advising privately can promise a timetable. Vetting has its own duration, and the employment-based classification used afterwards is subject to admissibility review and to visa availability published monthly by the Department of State, which is outside any adviser's control.
Do not give notice on the strength of a promised date
The practical risk with a new or evolving program is not that it fails but that a household reorganises its life around a schedule nobody is in a position to guarantee. Employment, schooling, a house sale and the winding down of a business are all decisions that are expensive to reverse. The safer sequence is to keep Canadian arrangements intact until an actual decision is in hand, and to treat any date offered by an intermediary as an estimate with no standing.
Hypothetical example: a grain-bin erector reads an announced processing timetable, gives three months notice to his employer and lists his house, then finds that visa availability in the relevant classification has moved and the wait is materially longer than the announcement suggested. Two safeguards cost nothing here. Keep employment and housing arrangements reversible until a decision actually exists, and put any date an intermediary offers into writing so it can be held against the official material.
Where the two disagree, the official material governs.