Do moves that decrease stats (accuracy, defense, attack, & etc) stack?

Solution 1:

Yes, stat modifying moves do stack. When the modifier reaches its limit (which does exist - 6 modifiers up or down, or a max of 4 times or 0.25 times the original stat), the message upon trying to modify the stat again will be something along the lines of "Vulpix's attack won't go any lower!".