Got to say it doesn't even sound good. Messing with some good pineapple jelly like that. But it's your taste buds. :-)

The acidity of the pineapple juice should be plenty to cover it as long as you don't get carried away with adding it. Of course you can always add additional acid - I'd use bottled lemon or lime juice not vinegar - for an additional margin of safety.

The reason the dried spices can work is they rehydrate in the liquid of the other ingredients so get acidified in the process assuming the other ingredients are sufficiently acidic.

Dave