I can provide you with lots of information in relation to Pop Warner at WDW during first two weeks of Dec as I am a patron who frequents during this time annually, (but not at the all-star resorts) and I am also a Pop Warner Football Coach. If anyone wants additional information please PM me...
Basically during this time there are approximately 8 teams per level (4 levels) and per division (2 divisions) for football for a total of 64 teams of up to 35 players per team, same with the cheerleaders (30 per team). So during this time there are roughly 128 teams from around the country competing for a super bowl and/or national cheering title. In total Pop Warner brings 3500-4000 kids to compete, plus coaches, family & friends for an approx total of 8,000 - 10,000 guests affiliated with Pop Warner during this time. They primarily use the All Star's then overflows go to Pop Century. Sometimes this can also overflow into some of the moderate resorts (I've seen them at both CBR and PO both during different years). My guess is if the value resorts are full they use the least occupied moderate to fulfill their reservations needs.
I have had both positive and negative experiences during this timeframe when interacting with different Pop Warner groups. As with any large group of children they are as well behaved as their chaperones/guardians permit them to be or not to be...