I believe you'll be fine

It's unlikely for your case to be processed within 6 months, considering many more cases will be filed next month, so AC 21 will be kick in after 180 days.

If you have RFE regarding EVL 6 months after 485 filing, you only need to provide the future employer's EVL.

To make it clear, if your 485 is processed after 180 days, as long as you have a permanent similar position as current one at the time of 485 process, it doen't matter if you are fired/laid off/stay home.