Rtmp using websocket
It is definitely possible to stream RTSP sources (or any other source streams) using websocket streaming. Any streams that exists on EMS can be delivered/streamed through the websocket player.
The latency of the websocket player is better to that of RTMP. And to further decrease the latency, you can play around with the GOP settings of your encoder.
Multiple streams support on the same page is undergoing development and will be available on future release. Right now, you can encapsulate the player through an html iframe tag and see if this would address your need.
A sample websocket player can be found here: http://ers.evostream.com:5050/demo/evowsvideo.html
Lazy pull mode is currently not supported through the websocket player.