I work in retail and have a few questions, so please bare with me. First, in New York, are employers required to give time and a half on holidays (ie: New Year's Day)? I've received it from a previous employer and don't know what to expect on my coming pay check.

Second, is it lawful to cut hours after a weekly schedule has been posted? I've heard it said that it's not, yet I've been scheduled to work 24 hours in a week, then had it cut to 8 after an email from our District Manager told the store to cut hours. It's certainly not fair, but is legal?

Lastly, if you work more than 6 hours, NYS law requires a 30 minute unpaid break. Got that. But does the law allow for longer breaks for longer shifts? I've been scheduled to work 9-6 and had at least a half-hour unpaid and one or two 15-minute paid breaks. What does the law say?

Thanks for the help.

No, only Massachusetts requires premium pay for working certain holidays in the retail industry. New York (and all other states) don't.

No, it is not illegal to change the schedule after it is posted.

There are some additional requirements for breaks depending on the time you start work and end work. However, a shift of 9-6 does not require an extra meal period; you would have to work until 7 for it to be required. See here:
http://www.labor.state.ny.us/workerprotection/laborstandards/employer/meals.shtm

New York does not require rest breaks.