Loads of question there! Lets see!
1. These armors or shields with 4os, are used in specific builds. Concentrating on one thing only, like glasscannons.
You can put 15ias/15max jwls in them or 15ias/40ed jwls. Or -5/+5 Lightning RBF's for those damn sexy Fist of Heaven Paladins.
Lower level gear of the same type cant use those jwls. But +9 or +11 jwls are damn good for some. IN those kind of items.
2. One of those. Magical items can have tops 2 affixes. One being Jewelers(4os) and one giving one of those 3 affixes I mentioned.
*Note: Rares can have 6 affixes. 3 suffixes and 3 prefixes.
Heres a good site for affixes! (The server is down atm, ill give you the link laters!)
3. ALready answered I think.
4. Ill post the link later. Its from a great German site Ive used for years.
The +100life/4os armors does exist! And they can even be bought from vendors! But they are insanely rare! Ive played a massive amount of hours and my best had 91 life.
Regarding Pupils vs Lightsaber.
-Ignores defence. Ignores defence! :P On all non unique monsters. So no bosses for instance. (Still 95% hit is max.)
-Elemental dmg will do alot less dmg in hell due to normal monsters natural resistances.
-Deadly strike will make up for its lower attackspeed.
-Open wounds! A chance to trigger a lvl dependent ("poison effect") removing the targets hp-regeneration (which is way higher in Hell) and does some physical dmg over a few seconds.
Its all preference!
Regarding the Pul to invest! I wouldnt get stormshield, because there are plenty of nice runewords for shields that you can use! Check out this, a favorite:
Any shield. (Get a paladin shield with as much @res you can find!)
Runes: Ko + Ko + Mal
Required Level: 49
+20% Faster Hit Recovery
+20% Faster Block Rate
20% Increased Chance of Blocking
+130-160% Enhanced Defense
+250 Defense vs. Missile
+20 To Dexterity
All Resistances +50-70
Magic Damage Reduced By 7
Level 12 Slow Missiles (60 Charges)
I understand this may be out of your budget atm, but will for sure be a viable choice once you get the runes! And you will!!
A cheaper alternative would be to get a nice 4os Pala shield, and put 4x Perfect Diamonds in it! Should be easy to get +90@res that way!
If you dont want to sacrifice a Pul for upgrading your weapon, there will be a ton more interesting drops coming once you reached hell difficulty.