For most procedures, especially things such as headlight removal, just do a quick search on this forum and you'll find everything you need.
For example this explanation of the procedure
came up in the search results.
In regard to your other two questions...try eBay, there are several people selling replacements, and a quick Google search will turn up several more.
I haven't had any issues with my electrical system or my head or taillamps, though I have a 97 so YMMV.
12 Wrangler Sahara JK8 conversion, <10 miles (FOR SALE, $56,700)
01 WJ Limited, 4.7, 247, black on black, 157k miles (sold)
96 XJ Classic, 4.0, 242, black on grey, 267k miles (sold)
00 XJ Sport, 4.0, 242, fern green on grey, 76k miles (sold)
90 XJ Wagoneer, 4.0, 242, burgundy on tan, unknown mileage (sold)
97 ZJ Limited, 5.2, 249, black on black, 138k miles (wrecked 12/15/05)
98 ZJ Limited, 5.2, 249, burgundy on black, 197k miles (sold)