I’m not sure this is clear. The chemical processes behind partial combustion of PVC yields HCl as a by product. I’m not seeing anything anywhere that talks about HCl as a byproduct of burning NaCl-laden organic material.
There is some evidence that burning driftwood produces more dioxins than the average wood, but if your ventilation system is good you should be ok. As always, be aware of the risks but also be reasonable about them. Dioxins are bad news, but it’s all a question of how much exposure you get… good ventilation should minimize that.
Check out #4 for more: