The chain is rated for 5400 lbs
The backhoe has a pin dropped in at the main pivot so it cannot drop
Because each strap / chain is "separate", there is redundancy. I always use 4 tie downs (min) when moving heavy equipment at work for much larger pieces of equipment and have never had any issue at weigh or inspection stations
Not sure what "it is not being held down" means (the chains and straps are both pulling the machine down). As I mentioned before, by far the highest and most frequent loads on the tie downs is the equipment moving forward during heavy braking
The rear chain hooks are welded on but you could also go to the "hitch mount" on the back of the tractor in front of the BH