The packs are very likely to still be available on Taiko no Tatsujin Plus, the current mainstay of Taiko on iOS. Yet, we can't say for sure for KAGEKIYO and Soul Calibur II, the exclusive bonus for purchasing the separate app versions. As a trivial note, KAGEKIYO is (soon "was") the only song on iOS to have an existing Ura notechart not included.
We will of course be keeping updates to the whereabouts of these two songs, as well as the whole Taiko Plus game. Check back when we see if more concrete reports emerge after the service termination.