State tax filing

You will need to file tax returns in states where you lived and/or worked:

1. A part-year Delaware income tax return, because you were part-year DE residents
2. A part-year New Jersey tax return because you lived and worked in NJ
3. A New York nonresident return because your wife worked remotely for a NY-based company.
   
   New York follows the convenience of the employer rule. If your wife is considered NY-based, then she is subject to NY state tax.
   
   Your wife's employer should have withheld Philadelphia wage tax so you do not have to file a Philly return. Employees who are working from home due to a business closure are considered to be working in Philly.
   
   New York City does not tax non-residents, so there is no NYC tax due.
    
4. You can claim an other state tax credit on your DE return for tax paid to NJ while you were a resident of DE. You can claim a credit for tax paid to Philadelphia and New York state on the New Jersey return. You will have to manually enter the NJ amount on the DE return and Philly amounts on the NJ return. TurboTax should calculate the NY tax credit on the NJ return if you prepare NY before NJ.
5. Yes. Income earned from your NJ employer while living in DE is taxable to DE.
6. Yes. If your wife received a corrected W-2c you should use those amounts and check the box W-2 was correct by my employer (Form W-2c) on Let's check for uncommon situations
7. You do not need to allocate your wife's income. You should say it's 100% NY income
8. You do not need to complete the NY business allocation