Yes, but beaches can get very busy depending on the day and time of day with designated parking filling fast. Waimanalo kind of fits this description but parking places seem to open up on a regular basis. As long as you are not blocking a road or driveway, police are pretty lenient.

We stayed in a home on Waimanalo Beach down from the camping area in March 2017. There were some homeless people staying more along the beachline in makeshift tents but they were harmless and very nice. They mostly kept to themselves. Most were not locals - we met a couple from the US actually that purposely went to Hawaii homeless. There are homeless all over the Island just like in the US. They mostly stayed in their shelters until evening and we saw them fishing and at times going through trash for recyclables. They were always very polite and friendly. We stayed 8 days and never felt like we were in any danger. We walked around at night to the few restaurants and went to the beach to watch the moonrise. I used the public restrooms once and found them usable - not extremely clean but not disgusting either. Waimanalo is a gorgeous beach - very private and we've even seen it in commercials after we returned home. It is used mainly by locals who are all very friendly and welcoming. If you walk down the beach towards the south, you will come to a huge reef filled with colorful fish and sea turtles that you can snorkle with. I would go back tomorrow if I could :)

I visits in November 2016 and some individuals were living in makeshift housing towards the Makapu'u side of the beach area. We walked down the beach towards the Bellows Beach side and felt safe. The presence of a manned Life Guard station was reassuring.

"The Bus" goes just about everywhere on the island. Check their website for routes.

Cant recall seeing any BBQ's but there is a toilet block and camp area, so its possible.