We own at BWV but booked the Beach Cottage in October, so it was only 5 months out. At that time, February was booked solid, and Easter week was booked solid. We were able to pick and choose various dates in March and we settled on 4 nights (Sun-Wed) and then dropped Wed in favor of an extra day at WDW. The points killed us at 78 per night (prime season). We would do a Beach Cottage again in a minute, but not when the points are so high.
Regarding boat rentals - I honestly didn't pay much attention as the area had severe riptides and waves (remnants of the Northeast blizzard the week before) and we wouldn't even have considered going out in a kayak or jetski. I do recall seeing jetskis for rent during our last trip there in September - can't tell you how much.
Regarding chairs/umbrellas. Yes - they do still rent them. It was $18 per day for 2 chairs and 1 umbrella for members - a little more if you are a non member. You can leave the beach and show your receipt later in the day to get the setup again (if you decide to take a break for lunch or whatever).
The only other item we rented on the beach were boogie boards. They were $7 each for the day.
Jenn