Do the bubblegum bullets already pierce? I may have just not seen that detail but information seems to flip flop between them being able to and not being able to...actually being able to shove the Destroyer in a small room and spam bubblegum bullets can be really broken, I'll assume they dissipate on first hit. Also with Bubblegum Bullets being made, what about a blue/normal gel equivalent? Pink gel made things bouncy, blue gel made things sticky. Just an idea to work with if needed.
For Sealing Arrows I'll assume they will take care of just about all the debuffs Ankh Shield could prevent along with a few other basic ones like Chilled and Frozen? With a lot of utility that could be brought into arrows like this, it'd be smart to add in some quick way to exchange between ammo types. When you want to start a fight with Sealing Arrows and deal the real damage with something like Hellfire Arrows, it's inconvenient to switch between them in your inventory every time you want to renew the effect. This is probably something that should be made separately, however. But would be really helpful with utility ammo.