Can I upload a zip file with htmls or a zip file with json files using the Web Interface of Watson Retrieve and Rank service ?
No, the web interface doesn't support that. It will let you upload multiple doc/PDF files in parallel though, without needing to zip them (up to 50 at a time)
But if you've already got your content in the right JSON format, you can post it directly to the R&R collection (e.g. Using curl or your scripting language of choice) without the web interface anyway.
The content will show up in the web UI when you come back.