You are allowed 5 people in a 1BR, even though it says 4...they will let you book 5...we did it twice. We had to bring an air mattress and bedding and towels for the 5th person. So, a 2BR is a 1BR and a studio (which allows 4).
It can be done, but will be very wild. Reminds me of the time we stayed with SIL's family at the beach...in her 2BR condo...with her DH and 3 little kids...me, my DH, my DS-2 and 3 month old twin DDs. It was a few days after DH had the snip-snip and it was on the 3rd floor...no elevators...in the heat of summer in NC. Good times!!!