Yes, your topic is a waste of text. What topic isn't?

Anyways, Combos mean that is how many hits you land on an opponent before they can recover and use another attack (or action for that matter). Double score is dependant on how high you can get that combo.

While it is random, it really isn't. I just don't know how the game computes it, but it may have something to do with how many times you can land a large-hit-combo in a row, (50+ hits, 5 times in a row, each time must be done with a different combo period, something like that) or cumulative hits that are in a combo (a total of whatever number, E.g., 5+5+60+7+190, based on amount of hits landed over the Stages).