There's a few issues here. Your pathfinding grid wasn't lined up with your tilemap solids, and they were different sizes. For exact tiles, you'll want to use a -1 cell border size. Set the pathfinding cell size to 64, the same as your tilemap cell size. Make sure your tilemap origin is at 0,0, to align with the pathfinding grid.
For moving to waypoints without cutting corners, you want to use the MoveTo behavior's 'Move along Pathfinding path' action, instead of the Pathfinder behavior's 'Move along Path' action. The pathfinder behavior will start turning right when it reaches the edge of the waypoint cell, while the moveto behavior will move to each waypoint location. The example project has a turning radius that takes exactly half a cell to turn 90 degrees at the speed it's going, which is why it works.
There is no need to update the path for each object regularly as you had in event 2, this can also contribute to cutting corners.
See updated example here - dropbox.com/s/e5601def28z8zeb/ballons.c3p
Edit - It's unfortunate no one helped you for so long, these forums are usually pretty responsive. Personally I usually look for posts that don't have replies to reply to, so I might have missed it when you replied to yourself, thinking you already got an answer.