iWatch without iPhone.

Depends on what exactly you mean by "function without an iPhone".

The Apple Watch absolutely requires an iPhone to setup. Once setup however, the Watch can be away from the iPhone and still perform certain actions. What it can do when away from the paired iPhone will depend on whether its a cellular model or not and if there's Wifi it can connect to nearby.

See here: How to use your Apple Watch without your iPhone nearby - Apple Support

Not at this time. If you have a cellular watch, after pairing with an iPhone it can function without having the iPhone nearby.

No it cannot.