So being able to cast protection from Evil (or other alignments) is worth a +1 LA? PFE can be cast by a first level character and even at level 1 has a duration long enough to last an entire combat. Yes being immune to most of the enchantment school is an issue but it is an issue across the game and is one of if not the easiest immunity to get in the game. I don't rate this immunity very high because it can be replicated so easily, it isn't worth an LA.
There are a few of poisons that cause sleep, pretty sure the only reason elves have that ability is to combat drow...
Actually I am not sure that rule is worth the ink it was written with. First of all it calls the elf's ability a resistance, but its not a resistance it is an immunity (granted they maybe talking about elf's resistance to enchantments and not sleep and just screwed up). Second of all it talks about letting yourself fail a save which brings up a host of issues. For starters immunities bypass saves altogether so you never get to the point to make a save and therefore can't voluntarily fail it. Secondly in the case of bardic music specifically, inspire courage, inspire competence, inspire greatness, inspire freedom, nor inspire Heroics allow a save.