EB2 Green Card

I entered the US to complete my Masters on an F-1 visa in 2018, I got my H1B visa approved in Oct 2022. I was planning to go for a green card through the EB2 NIW route. I have a few questions, which are as follows:

1. Suppose that I got EB2 NIW approved and I am waiting in queue for a green card, but I went back to India and worked in India (employer may or may not be related to the US). Can I collect my GC whenever the priority date becomes current?

2. Suppose that I have already applied for an EB2 NIW visa but then I build my profile and want to apply for an EB1 visa, can I do that?

3. When can I start my business/startup during the EB2 NIW application process? or Do I need to wait until the visa is approved to start a business?

4. When can my wife start working on an H4 visa? Is it during the EB2 NIW application process? Does she need to wait until the visa is approved?

I am currently doing my bachelor's in Computer Science outside the US, my goal is to work in an industry that generally doesn't sponsor visas. I was born in Canada, so just a ROW backlog. Since I can't rely on anyone sponsoring H1B or even TN(also not a TN classified job), I will need a green card before working in the industry.

I'm wondering how difficult it is to get an EB2-NIW with just a bachelor's (exceptional ability), can you explain the process and criteria for this if possible?

My field is adjacent to AI/ML right now I'm doing an internship as an Undergraduate research assistant and by the end, I should have 6 internships (not sure if this helps). The criteria I'm going for (obviously just a guess right now) I'm planning to get a few certifications for AI/ML (from reputable organizations).

I will have a degree in the field. I'm already a member of a few organizations in my field. I can get my professors, managers during my internships and other peers, to write recommendation letters for me.

Can you provide some context as to what they are looking for in this category and it would be great if you could give some recommendations on what I can do to build a solid case. I'm already a member of a few organizations in my field (eg: IEEE and BCS)

My perm got approved on Oct 5, 2023. I am an Indian citizen with a priority date from my previous employer filing as March 28, 2012. As per the Oct 2023 visa bulletin, I am current under the “Dates for Filing” chart for EB2 and the “Final Action Date” chart for EB3. My employer's immigration firm insists on filing my I140, I485, I765, I131, and I693 under EB2 instead of EB3 for my case. So two questions:

1) Can you please explain the pros and cons of filing under EB2 and the pros and cons of filing under EB3?

2) As the EB3 “Final Action Date” chart is current for my priority date. Wouldn’t it be better for my case to be filed under EB3 instead of EB2, ensuring my 485 will get decided faster if filed under EB3 instead of EB2? Isn’t it?

I have an EB3 I-140-based EAD currently. If I set up a software firm for myself, can I sponsor EB2 or EB1 I-140 for myself? The main reason why I want to sponsor myself is I would not be under the constant fear that my employer may withdraw my I-140 for one or other reason. I will be able to work for myself. Is there any rule that stops me from filing an employment-based immigration petition for myself?