Is there a metro rail to get to the ferry terminal to Hong Kong from Shenzhen City centre?

Head for Shekou ferry Terminal from where you are. There you can take a ferry to HK.

Thanks. We booked an accomodation in Dongmen ZTL Hotel. How do I get from the North railway station to the hotel by public transit and long does it take. Similarly, from the hotel hotel to Shekou ferry, how do I get there by public transit and how long does it take?

From the north station to your hotel, you can take subway Longhua Line to Children's Palace, where transfer to Longgang Line and get off at Laojie station. Leave through exit D and you can see your hotel. The whole trip takes around 35min.

To Shekou Port, walk to Laojie metro station to take Luohu line to Window of the World. There you can easily transfer to Shekou line to your destination. It takes around an hour.

Thank you. That is very helpful. Can I confirm that the last ferry from Shekou port to Hong Kong for a Friday night is 4:45pm

Yes, you're right. The last ferry is 4:45pm.