Nothing can really hurt your granite. Some colors MAY show some oil staining if not sealed, but granite is much sturdier than marble, which can easily stain. I've had my granite counters for 13 years. They are a mottled golden brown agains my unstained cherry cabinets. My husband does use some sealer about twice a year and purchases it from Lowes or HomeDepot.

It is very smart that you are vetting the fabricators. Definitely seal the inside of all holes. A true quartzite will not etch but some are more porous and benefit from sealing. If you do a search above on 'quartzite staining' you will pull up numerous threads from posters that have had issues. Our quartzite was installed two years ago. We have two sinks each with three holes. One soap dispenser hole was accidentally not sealed and it developed a shadow around the hole about a month after installation. We removed the pump head immediately and when it dried out our fabricator came back and sealed the inside of the hole. Since then we have had no problems. Before choosing a stone I would read karin_mt's threads on here and the helpful articles that she has written. I would follow her recommendation and test the stone that you plan to purchase. In the tests that I did at home some samples that were marked as quartzite failed miserably with etching and staining. https://usenaturalstone.org/properties-of-quartzite/?utm_source=related-articles/ https://www.houzz.com/discussions/2438427/countertop-geology-part-5-marble-quartzite-and-other-favorites#n=165

Ask your builder. You will need to reseal in the future but normally unless there are things in the contract that are specifically stated as buyer finish the day you receive the keys the house should be move in ready. Move in ready normally means that nothing needs to be done. However there will always be things found that were not completed correctly or simply left undone. It will depend on the state laws and how you are purchasing and your lender's requirements and inspection will be done. A walk through with a clipboard before final close beyond any official inspection is always a good thing. Ask the builder about doing this. If you see anything that seems odd to you make a note of it on the clipboard. At one time builders were more relaxed with these inspections but may limit who and how many are allowed into the dwelling. Plan on wearing booties and face masks. The booties are to prevent any last minute dust, which there will be, from being tracked all over. The face mask is because along with the chance of virus there will be dust in the air. Things I would look at and write down are anything that looks odd be it a difference in how the light reflects off of a hard surface or a line in the carpet when it was from two batches. Electrical outlets secure. There will always be at least one that is loose. Open and close all of the windows, all cabinets, and the garage doors to make certain they work and are easy to move. Sometimes depending on the grade of builder you may need have a long list. Other builders especially when they are aware of what you are doing your list will be small. If the list includes things that are just not to your taste unless they are mechanical or electrical do not expect the builder to correct. Always have your significant other with you it helps for family harmony.

Dawn Platinum has a ph level of 12. Oven cleaner is 13, so you've etched it. It's probably fixable with a Quartz Renew kit and an experienced technician. Absolutely not a DIY, as you've discovered with the MB. If I got this call, you'd acknowledge in writing that the top was ruined and that I couldn't make it any worse or I wouldn't come. If you didn't like the refinish, you'd owe nothing. If you did you'd owe me $1,500.00 or so, just less than replacement.