Yes, you can start the STEM OPT. The NIW petition (I-140) has no impact on your immigration status.

Yes, it is possible to apply for an OPT extension while your I-140 is being processed.

No, your NIW denial will have no effect on your normal I-140 application.

Yes, the organization can apply for your H-1B while your I-140 is being processed.

Submission of I-485 application depends on your current status. If you need a work permit in the next 4/5 months, apply for I-485. But if you do not need any work permit in the next 4/5 months, I would suggest not submitting I-485 and waiting until your I-140 gets approved.

Yes, you can. Your I-140 petition has no effect on traveling outside.

No, your I-140 will have no effect on the F2 Visa. In both cases, your I-140 will have no effect as they are in no way co-related

Yes, you can. A letter must be sent to the USCIS stating that you want to withdraw the petition.

There is no impact of the H1B transfer petition on the EB2- NIW application. So, we can proceed with the EB2- NIW application.

NO. It will have no impact on the NIW application process.

Yes

If you applied only for the NIW (I-140), your travel would not be affected. However, if you have also submitted an application for I-485 with it, this will affect your travel if that process is ongoing.

Yes.

No, it won’t affect your case.

Not all J1 visas come with a Two-Year Home requirement.  If your J1 visa comes with such a requirement, you must get a waiver before submitting your I-485.However, for I-140 there is no difference between an F1 visa and a J1 visa.

Both. You can find more details by searching for the J1 Waiver application on Google. You will find all the necessary information there.

It should not pose a problem since both of them are different.

NIW has two steps. The first step is I-140, which is only for you. After your I-140 is approved, the next step is I-485(Green card, EAD, Advance Parole). Here, your spouse will be added as your derivative.

It depends on your VISA status on which you are currently residing in the United States. It has no connection with the I-140 application.

Yes, the NIW petition (I-140) has no impact on your immigration status.

However, if you file I-485, you cannot apply for OPT or an extension of OPT until the I-485 application is decided.

Yes

It usually takes 6 months to proceed.

Usually, it takes 7 months. But depending on the service center, it often takes more than a year. You can certainly concurrently file I-485. The benefit is that you will receive EAD and advance parole under which you can work and travel. However, there are some risks involved. Since I-485 is an immigrant application, your F1 status will be abandoned. You will not be able to apply for any non-immigrant status (e.g. OPT) while your I-485 is pending. In case your I-140 is denied, you will be out of status. Filing only I-140 will not affect your non-immigrant status. We recommend concurrent filing for those who are nearing the end of their non-immigrant status.

NO. It will have no impact on your spouse’s application process.