"in doing so and living in NY part-time, would i have to pay NY income tax? assuming I'm there more than 183 days and if so, would I be eligible for the double tax credit?"
Yes. If your situation becomes one of dual residency - which it will if you maintain a permanent place of abode in New York State for substantially all of the taxable year and you spend 184 days or more in New York State during the taxable year - then you may claim a credit on your NJ return for the taxes paid to NY on the income taxed by both states. See this NJ tax publication on this issue:
https://www.state.nj.us/treasury/taxation/pdf/pubs/tgi-ee/git3w.pdf
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
