I came by to try to make an order last night around 7:30 pm, and it looked like the restaurant was closed. Are they still open for business?

Yes

Yes they stay busy during the day and people order carryout a lot in the evening.

Yes, still open

It was a Friday night at about 7:30. That is why I thought it was strange that the lights were out and no one was inside.

Yes they are probably closes on Sundays, most Chinese restaurants are