Hi, we are just back from VB for the first time (early August for 3 nights). I can't say what it is typically like, but I can try to answer your questions based on our experience!
1 - The resort was really booked up, and I am sure the only reason we got the 3 night stay was due to a cancellation (we probably booked about 2-3 months ago). But it didn't feel really crowded, not in the resort area, nor the beach or the pool. Not that it was empty either, but no issues re: crowds. Weather was HOT. HOT. Did I say HOT? It's just really humid, and in the 90s, it felt like 100 most of the time. BUT, that makes for great beach nd swimming weather. It also is the start of tropical storm season, and we narrowly missed an impending storm or two and got lucky. Nothing serious, just more rain. That time of year pop up afternoon/evening storms are pretty typical (we only had rain the day we arrived for our entire 3 night stay).
2 - We were not in tune with all the turtle activity. I believe the tours at night or in the morning were just ending the week before we got there (so pretty much end of July). Maybe somebody else can correct me on this, again, not a turtle expert.
3 - Not much to do other than beach and pool. There are kayaks and bike rentals as others have mentioned. I did see people on kayaks, and some on jet ski's. It was much too hot to rent a bike. I wouldn't have wanted to kayak either. The ocean on the other hand was VERY refreshing. Within walking distance, there is very little else to do. But what I really liked was waking up in the morning and not having to scramble to get ready for a park opening due to all the lines, etc. It was just nice to wake up when you wake up and not feel pressed to go anywhere or do anything.
4 - Food options were so-so. Think your basic counter service place and basic sit-down place. And what they have there is expensive, especially considering you are not in the middle of WDW and local restaurants are much more affordable. We actually didn't frequent either place so I shouldn't say too much. We had a car and got breakfast and lunch groceries, then ventured to various places for dinner. Maybe consider an uber to go to Publix or making a stop on your way. It was much more inexpensive and convenient (and you can eat what you like).
5 - Yes, you are able to rent chairs as others have mentioned. We brought a blanket (small portable one from home) and used that to stake our space, and didn't rent chairs. We found that we spent about an hour, maybe 90 minutes top at the beach, then moved to the pool area. Most of the time we spent at the beach was in the ocean. It was really hot, and just sitting around lounging all day in a chair would have been a bit unbearable, unless you dipped in and out of the ocean regularly, but frolicking in the ocean was a highlight.
My DS is 12 and we enjoyed playing Pokemon Go at the resort. I know it's not of great interest to everybody but we had fun with that. Other than it's all about the beach! We were there 3 nights and that was about right.