Info and advice about TnR?
Just leave them alone. The sea salt spray is good, but don't leave it in long. Just spray it on maybe an hour or so before you wash. If you leave it in too long, it will irritate your scalp and cause itchies.
The tips should not lock. If they do, it's ok, but it's better for your hair if they don't. Those wispy ends help water drain out of your hair. If you blunt them, water will get stuck and make it a pain in the butt to dry. If they blunt on their own, let them, but don't try to force it.
The roots will mat eventually. There's nothing you need to do to lock them. Look at pictures of mature dreadlocks. They were not always that long. it takes years to form fully mature locks. In those years hair still grows. If the roots didn't lock, you'd see a few inches of lock, and then the rest would be straight hair. There will always be an inch or 2 at the root that isn't matted. But in time this will tangle too.
Check out this link. It gives a decent list of info for new comers to the dreadlock world: