I bumped the life trick thread since there are other relevent details to it (it was detailed in BSiron's FAQ), but for the most part there are some interesting notes with that. Refer to this thread:
http://slickproductions.org/forum/index.php?topic=151.01) Even though Break/Stone kills the enemy, it's current status is retained and thus Life2 refuses to work.
2) Most enemies tend to continue their battle script, but they tend to "counter" you with their spell counter script upon revival.
3) My only guess is to why Life2 works is that there is no discernable equivalent enemy Vitality/Stamina stat to derive the HP for the enemy revival, thus it failing hard. Life2 revives the enemy to maximum HP (though, it is untested at higher HP threasholds...)
4) It may simply be the high defense at work, but reviving Flan/Pudding monsters seem to prevent even high physical powered attacks (including Jump) to do any decent damage on the revived monster. Something goes screwy in the battle engine to keep the monster becoming nearly invulnerable to physical attacks. Killing another monster or kill the revived pudding/flan monster with magic will fix this behavior.
5) Note that Life2 works different from the monster's "Call/Summon/Alert", since monsters generated by the latter tends to have all statuses removed, whereas Life2 does not do that (which make sense, but it's an interesting distinction worth noting). So, you can see revived toad, piggy, and/or small monsters be revived by this method... keeping them in a continuously harmless state.
I can't think of anything else off the top of my head, but I'm sure this may be helpful somehow.