1) Buy a Haynes manual (PN 36058) and follow the instructions in the last chapter for removing the cluster. You can also click my signature link & look in the Low Fuel Light album for some additional info.
2) Wal-Mart's bulb finder computer shows the correct bulb. It's a large wedge-base, but IDK the PN.
3) What part are you trying to buy? The "lock" is an integral part of the latch. The lock cylinder (where the key goes) is probably fine, but it's common for the plastic lever on the back to break off. IIRC, adrianspeeder posted pics, PN, & price for it on FSB
, and probably here too. Do some searching. You can find several diagrams in the Doors album in my signature link. If this problem surfaced when it was freezing, read the recall about the door latch near the bottom of this page