Messy layoff question - NY State

Location: New York

Background: I was laid off from a small company due to financial setbacks. I was based in New York City and worked exclusively there. My employer's US office is based out of another state. After being informed of my layoff, I negotiated the following terms with my employer, which were agreed to via a letter sent via email:

• 3 weeks of pay from the day I was informed of termination
• Healthcare coverage through the end of May
• No formal severance agreement was ever sent or signed - they instead sent a letter summarizing these terms we agreed to and I confirmed via email

Here are the issues I'm dealing with:

1. Benefits terminated before layoff notification My health insurance was terminated approximately three weeks before I was informed of my layoff. I was still an active employee at that time with no knowledge of any impending termination. I only discovered this when I showed up to previously scheduled medical appointments and was told I had no coverage. I have had to reschedule care and am attempting to coordinate a surgery before any remaining coverage expires. I also never received a COBRA notice and they were supposed to cover my healthcare through end of May.

2. Severance agreed to via email - no formal agreement signed After negotiating, my employer agreed via email to 3 weeks of pay from date I was notified of my termination and healthcare coverage through the end of May. I accepted these terms in writing via email. No formal severance agreement was ever sent or signed. I want to know if this email exchange is legally binding and whether he can still require me to sign something with additional terms.

3. Wages reported in wrong state It has been confirmed by the NY Department of Labor that my wages were reported in a different state. As a result my unemployment claim cannot be processed in New York. This may have also impacted my tax withholdings throughout the year, potentially causing penalties. I am also currently ineligible for NY unemployment because of this.

4. Missing tax documents I have not received my 1099. I transitioned from contractor to employee during my tenure.

5. Vacation pay My contract explicitly states accrued unused vacation must be paid out upon termination. The company had no formal system for tracking vacation days. I am owed approximately 10 days of accrued unused vacation. I have not raised this yet.

My questions:

1. Is the letter in the email exchange a binding severance agreement? I did not push for a severance agreement as it usually only serves the company and I also want to make sure they will pay me for vacation days (they were originally not offering any severance).
2. My benefits were terminated weeks before I was told I was laid off and this goes against the agreed terms. I missed doctor's appointments which I now may not be able to schedule (including a surgery). As they also terminated my benefits while I was still fully employed, can I request an extension of benefits?
3. Are they responsible for any penalties, fees, or damages resulting from wages being reported in the wrong state?
4. What are my rights regarding the missing COBRA notice?
5. Can I still claim vacation pay and how do I go about doing so?
6. Should I consult an employment attorney and do I have enough here for a claim?

They have handled all of this poorly and all of the back and forth has been so stressful. I just want to understand how to handle this moving forward so I can focus on taking care of my health and finances. Any advice would be greatly appreciated.