My employer is a small startup — can they even sponsor me through Ontario's new stream?

Employer requirements for the new stream generally include being registered/approved by the OINP director, actively operating in Ontario for at least 3 years (with some exceptions for new establishments in priority sectors), and meeting a revenue or headcount bar — roughly $1M CAD gross revenue, or at least 5 full-time employees in the GTA (3 outside it). At 18 months and 4 employees your employer likely does not meet the baseline unless they qualify for a priority-sector exception — worth them checking the official Ontario.ca page directly rather than assuming. General information from my own experience, not legal advice — for anything specific to your file, a licensed RCIC or immigration lawyer can look at your actual documents.