I can confidently say that changing the function(s) shouldn’t be an issue if you have the proper MySQL related functions available in your project. The functions simply take in a card array, which you can then set the variables stored within your database.
As for the booster packs, the more timely thing for this would simply be the UI and handling which cards are unlocked within your database. Simply getting cards within your game, and randomly selecting them should not be difficult. Adding things like selecting cards based off their rarity, card types, card sets etc would also add layers to the system, but even then it should not be difficult with filter functions already included within the toolkit. Like the Taunt, I can provide support and direction for adding something like this yourself.
Anyway, great to hear you are liking the sound of the toolkit, and let me know if anything else pops up that you would like to know!