It looks as though there might be a communal space at the shore at end of that dead-end street just north of the pool, too? There might be something you can use there. Just pay attention to that green line.
As for proximity… there’s only allowed to be one active wayspot in Pokemon Go, it can be either a gym or a pokestop, within each of those green boxes. There is no rules about where within the box… I have two that I nominated, that are both live, that are murals on opposite sides of the same fast food restaurant dining room (the line goes through the center of the room).