Seriously, it makes no sense to me! My player character is a Lv. 40 riolu with 126 HP, but the Lv. 55 shaymin that tags along in Sky Peak has 86ish HP! How does that work? Shaymin has a higher base HP stat and is a higher level.
Also, why the strategy guide say lucario has lower stats that it's per-evolution? Can someone explain how stats work in PMD to me?
If you raise a Pokemon from a lower level on PMD, It will usually have bigger stats than a Pokemon that is recruited at like Lv40. Riolu was your starter, which meant it has had more training, Shaymin has just joined and has had no training, and those stats are just the stats at Level 1, usually baby Pokemon have higher stats at that level, but you'll find if you raise a Level 1 Riolu and a Level 1 Lucario all the way to 100 you'll find Lucario with higher stats.
Base stats from the main series games play no part in this game.