Allow time for the corporate evidence before the petition is drafted, then USCIS processing, which premium processing can shorten. Where the subsidiary must first resume genuine operations, that period is the real constraint rather than adjudication time.
The dormancy, not the queue, sets the calendar
If the owners choose to restore trading before filing, the schedule is driven by how quickly the subsidiary can hold real customers, real payroll and real records, and a few weeks of thin activity assembled for the purpose will read exactly as it is. If they file as a new office instead, the calendar shortens but the first approval runs for one year, and the extension at the end of that year is judged on what was actually built: staff hired, revenue earned, premises in use.
Ingrid should also count her own clock, since the qualifying year abroad must fall within the three years before the petition and time spent waiting in the United States does not extend it. Requests for evidence add weeks, so build the file to answer the obvious question first.