I am not even sure you would get welfare as you are not a PR or a citizen. If you are eligible for it, then there are no concrete rules that say you can't apply for welfare while applying for PR but if your closed permit employer is the same one that gave you an AEO, immigration may question your ability to survive in Canada on the wages you are being offered or if the case is that you are laid off, they may question the validity of your AEO.
If you are short of cash, you can go to the food bank and there are also places where you can eat for free. That way, you can stretch your cash a bit further.