Not until it’s fully dry. That Sg of 1.015 means it’s still got a bit to go. Needs to finish below 1.000 to be considered dry. Normally lands at about .994-.998. Unfortunately that ball valve of sediment contained a lot of the active yeast making the final bit of sugar remaining more difficult to ferment.
noworries about Camden/sulphites yet at all. There’s plenty of co2 built up in there from fermenting to protect it for now. Main thing you wanna do is get this thing dry. Typically juice pails run dry in a week but slower ferments are not uncommon. Multiple factors play into it - but the active yeast being removed likely is the reason. Others may have different advice —- but my recommendation is to monitor that SG daily or 2x daily. If you see it dropping then just let it keep going till dry. If stuck at 1.015 then adding in some more yeast- a strong yeast like EC-1118 might be able to finish it off. Stuck too low abv is too high for yeast to be able to ferment residual sugar. You are close at 1.015. Keep that ball valve closed, stir it up daily, make sure temps are at or above room temp, monitor Sg, and let’s get that sucker dry!
If you do end up needing to add more yeast- you can add it in a way that will give it the best chance for success making a starter. Can cross that bridge later tho if it comes to it. Good luck