For the Free Live difficulties, you only have to remember one of them - you can then find the rest easily, as they're part of the Fibonacci sequence.

The amount of common Drops received depends on the played Difficulty and the achieved Rank.

Bags are guaranteed Drops at the end of a Live, based on the Formation's total Technique or the amount of Skip Tickets used.

When playing the Live, the Base Technique of all Units and Accessories in the Formation is summed up and used to decide how many Bags will drop. The Live will drop one Bag if the Minimum Technique for that Live is reached, and then additional Bags for reaching a certain amount of Technique past that threshold, up to the maximum Bag amount defined for the Live.

When using Skip Tickets, the Formation's total Technique is ignored and you get a fixed amount of Bags instead. A single skipped Live will always give a single Bag, but if using multiple Skip Tickets at once, the amount of Bags per Live will alternate between one and two for each odd-numbered and even-numbered Live. This means it is optimal to use an even number of Skip Tickets, to get an extra Bag.

Before the v2.0 update, drops from Skip Lives were displayed seperately, which made this obvious to the player. Since that update, Skip Live rewards are stacked, so it's impossible to tell which items came from which source in-game. However, that stacking happens on the client side, so intercepting the network traffic allows one to still check the drops from each Live seperately - showing that it still works the same way, even if it's not visible to the player anymore.