Frontier Airlines EarlyReturns (Pre-Alignment) - 3 basic mileage questions

What fare class are mileage seats booked in?
Can I assume if there are 6 open seats in that class I can redeem 6 mileage awards?
Is there a website that shows availability of all fare classes?

The F9 site only allows you to shop for mileage seats based on your account balance. If there are multiple people traveling, I'm not aware of an easy way to know availability. I'd rather not pay $25/ticket to have a ER member book this for us.

Thank you.

1 - I believe "S".
2 - I don't think so. I usually see either 9 or 0 and you are restricted to 4 passengers when using the on-line tool.
3 - seatcounter.com (there is a daily query limit)

thank you for the seatcounter.com reminder. i've seen that sight before, but couldn't remember how to locate it.
if BKCODE is fare class, then mileage seats are booked in U. after booking. the fare basis on my paperwork displays as F9MEX25.