Part 42: Current SituationSo, here's the situation.
Now that we're done with all of the Story Mode, a special reward is available for completing one of the Battle Modes, under special conditions.
Although we could've completed the Mt. Battle Vs. 100 challenge at any time, we will now receive a Pokemon as a reward for completing it from start to finish, with the same team (or, more specifically, without switching Pokemon or quitting). You can pause the challenge by quick-save, and pick it up from there via Continue. Your only other reward are PokeCoupons, much like the rest of Story Mode's Mt. Battle.
In order to receive the Pokemon, you must register a six-Pokemon team from Colosseum Pokemon. You are limited in your selections to only the Pokemon found on your Colosseum Memory Card. However, you can trade Pokemon to and from that Memory Card via GBA-GCN Link Cable, as previously covered, to use any Pokemon you want from Ruby, Sapphire, Emerald, FireRed, and LeafGreen. This makes the challenge considerably easier.
EDIT: Also, here's another source of some of the LP's delays.