I pray this message finds you in the best of heath and faith, insha’Allah.
No, swallowing the remaining taste of the siwak will not break your fast. [Shurunbulali, Maraqi al-Falah]
However, it would be best to spit out once after using it.
Atif Aslam refused to perform songs in Saudi Arabia, stating, “My heart does not accept performing songs near holy places.