Ask HN: Can I build an ElectronJS app on top of WhatsApp?

I'm looking to build an ElectronJS app with following features on top of Web.Whatsapp.com : 1. Password lock feature on web whatsapp. 2. Auto-replies to incoming messages, when busy. 3. Festival Greeting messages to upcoming events. 4. Hide any notifications on Web.Whatsapp when busy. It'll be an ElectronJS based wrapper service around web whatsapp. But, my query is: 2 of my old clients have requested us to develop something like this. So it's a commercial/paid sale of service on top of whatsapp web. We'll NOT use WhatsApp name or logo anywhere in ElectronJS app. And put a clear disclaimer of not being associated with Whatsapp or Facebook in any way. Will it violet T&C of whatsapp/facebook? Will it be illegal in any way in USA or other countries? To build something on top of Whatsapp web. Please advise in legal terms.