Ha, I just dealt with this (although mine is in a corner, not an alcove.) What a pain! We had a top made for us out of quartzite (like marble) and while I patterned the vanity perfectly, I assumed the corner it sat in would be square. It was NOT. I had planned to tile the wall first, then install the vanity and caulk the edges. What we ended up doing was basically what the kitchen counter granite installers do: We cut into the drywall, just a notch the size of the countertop, and slid the protruding corner into the notch. Then tiled down to the counter (rather than behind it) like a kitchen counter. So that's one option for you: get your granite counter cut larger and recess the front. But WAIT!!! You haven't had the granite cut yet? Why not just template the exact space and get the granite cut to fit perfectly? Otherwise, are you planning to tile the walls around the alcove? a) you could choose fat tile, which would cover the caulk line or gap. b) even if you choose thin tile, only 1/8" of your 1/4" caulked gap will show under the tile :)

This design site lists international building code and international plumbing code requirements which are supposed to be the minimum even in locales without local code enforcement, and then recommendations in addition to that. My locale is fairly lenient with code interpretation because of very old very small housing stock but as soon as you touch a bathroom, you have to meet the 15" and 4" requirements for sinks. ----------From the website---------------------------------------------- Recommendation: The distance from the centerline of the lavatory to the sidewall/tall obstacle should be at least 20”. Building Code Requirement: The minimum distance from the centerline of the lavatory to a wall is 15". (IPC 405.3.1) The minimum distance between a wall and the edge of a free standing or wall-hung lavatory is 4". (IRC R 307.2) Comments: A pedestal or wall mounted lavatory must meet both of the Building Code Requirements. The center of the lavatory must be at least 15" away from any side wall or tall obstacle, such as a tall cabinet, and the edge of the lavatory must be 4" from the wall or tall obstacle. There are practical reasons for the 4" requirement. Any closer and it would be very difficult to clean the lavatory. In a small bath remodel, careful attention needs to be paid to the size of lavatory sinks to ensure that minimum offset distances are met. When in doubt, go smaller. Almost all fixture manufactuters make lavatory sinks designed to fit very small spaces.

From Proline Range Hoods FAQ section: "The third variable which affects the effective capture area of your range hood is the size of the hood. You can have the strongest and most powerful vent hood, with the best design, and if you don’t cover the cooktop and trap the cooking exhaust you can never get rid of it. This is especially true for range hoods over island cooktops. Once you have considered your cooking style consider the size of the range hood. Try to size the hood 6” larger in width than the cook top. Most range hoods come in 22-27” depths with some of the range hoods being 30” deep. The more coverage the better for the serious cooks. If you use your cooktop and you are serious about cooking then remember “coverage is king” especially in an island range hood setting. You can also help yourself by trying to keep your cooking over the primary capture area of your range hood. BBQ and Heavy Smoke cooking environments, both indoor and outside need coverage so size of the range hood is critical. Again, if you can catch the smoke and exhaust you can get rid of it but if you don’t “trap” or catch the smoke it is almost impossible to get rid of without removing an inefficient unnecessary amount of additional air in the room. All of which must be heated or air conditioned in most cases." http://www.prolinerangehoods.com/1-801-973-3959/support/common-questions/

Rainiel, the OP doesn't seem to want to have it scribed to the wall. That was the first thing I mentioned, and the OP said she didn't know anyone who could cut the top without breaking it. I guess this is a DIY project, and there is nothing wrong with that. You have to save money where you can. Anna, I am with you on crooked houses! My house is mostly one story, but it has a three car garage with an upstairs room. It was one giant room plus a bathroom. Not useful at all. We have turned it into a bunk room, two bedrooms, and a sitting room. The crooked part? The entire garage and upstairs is a giant parallelogram which was NOT perfectly square. It was angled, for the lake view, I guess. Stupid reason to build a parallelogram. Some of the corners are 15°. Can't put anything there. But, my crooked stairs took top prize for crookedness. The steps were all different heights and depths. Some of the vertical parts of the stairs leaned forward and some leaned backward. We called them the "stairs from hell". About half way up people had to use the handrail to pull themselves up. As the stairs got closer to the top, whoever built them ran out of room....some of the steps were 6" deep to put your foot on, and some were 14-15" tall. Now, that is a workout! Good luck with your vanity, and show us pictures of your solution!.