Do I need to maintain in TN visa status when my I-485 for EB-5 is pending?

At this point you are a Pending Immigrant, which allows you to remain in the U.S. until there is a final decision.

You do not need to maintain TN status, but if possible, it is advisable to do so. If your adjustment is denied, you will have to leave or could be placed in removal proceedings.

Not required, but advisable.

In order to be eligible for adjustment of status, the immigration regulations require that the applicant be maintaining valid nonimmigrant status at the time the Form I-485 is filed. Therefore, it is not necessary to maintain nonimmigrant status, such as TN, while the I-485 is pending. It is recommended to maintain such status, however, in case there is some issue with the I-485. If the I-485 is denied, for example, then there would be no valid nonimmigrant underlying status and you would be required to depart the United States.

You do not have to maintain another nonimmigrant status with a pending I-485 but it is recommended to do so just in case there is any issue with your I-485. However, you may encounter difficulty if you wish to travel with your TN visa with a pending I-485.