Lich Bard's page

In a group of life forces, you can sense a difference of 4 or more HD between one creature and another and can determine whether a life force is powered by positive or negative energy. (Undead creatures are powered by negative energy. Only sentient undead creatures have, or are, souls.)

Even though this is probably a backhanded flavour text, it does state it. The soul may be corrupted, or separated from the actual moving body, but it's still a soul. Probably there is more information in books like Undead Revisited though.

And I agree the time limit is because the soul is decomposed in the outer planes. If someone dies, and its soul is bound, and 500 years later, the gem is broken, and someone tries to revive him, I would say it could.

Maybe the text is refering not to the time dead (physiologically speaking) but the time since the soul has been separated. If it's bound, (by a gem or by undeath) then the soul hasn't passed away.

First of all, I'm not familiar with the advanced class guide, so I can't say anything about those things.
Then, what is your style? Str magus, dervish magus? What are your weapons? How would you like it?
I don't like reflection very much, it's too expensive, and you have many arcanas, so those are going to be your main arcane pool-powered abilities.
If you are more of a dervish magus, I suppose you aren't going heavy on armour. If that's so, spell blending on mage armor can be effective, but a wand also can do the trick. Ghoul touch is a good spell for spell blending though, specially against spellcasters, who don't usually have a good Fort save.
Spell perfection doesn't change the level of the spell, right? You could have both effects, one from a feat and one from a metamagic rod. Remember that if it's shocking grasp, you don't need to discharge it in the same round you cast it. You could charge a SG with the rod, as a normal spell, put away the rod, so you have a free hand, and when you start your turn in melee with an enemy, spell combat him, a normal blow being charged with your metamagicked spell, and the spell of spell combat being another shocking grasp with only the feat you have. Also, when comparing both feats, remember that the magus can get a spell crit far more easily (usually) than other mages. A crit with maximized (intensified) shocking grasp deals 120, while a crit with empowered (intensified) SG, assuming that it deals 15d6 (empowering AFTER intensifying), are 30d6 from 30 to 180, while it's average is 90, being %75 of the other.

The magus is one of my favourite classes, if I think about anything else I'll post it. Hope this helped.

There is a very useful item, the swarmbane clasp if I remember right, 3000 gp, that lets you damage swarms with weapon damage. Apart from that, you have to use area attacks, in fact they take more damage from area attacks. Either spells (Ye Olde Fireball) or others, such as an alchemical bomb (not the alchemist's bomb, ones in the UE). For these situations, you should have a scroll, or a wand if you have the money, of burning hands or such.