Full disclaimer, I didn't use Waikiki co-working space, or their hotel. I just walked into reception, where a helpful young guy answered my questions, in near perfect English. And he let me take a look at the work area. It's nothing special, but if you want to meet like minded people when you arrive in Da Nang, this the place to go.
I hope the phone number on their website is connected to WhatsApp, if you want to stay in their hotel long term, 2 weeks or more, ask for special rates. And see what they can do.