Can we start mesh hosting from http://scratch.mit.edu.ezproxyberklee.flo.org/ ?

As fas as I know, not at this moment. I hope it will be added.

No. But you could make a project in 1.4 with mesh, upload it to the site, and tell people they have to download the 1.4 code for it to work.

I don't think so. It wasn't even fully implemented into 1.4.

cool games

In 1.4 it was,but It does not work,nobody will be able to connect to you.

This might be possible with a self-hosted server and scratch extensions, but it seems that nobody has researched that possibility significantly as of this time.

no but cloud data can be a workaround for mesh. http://mv.ezproxy.com.ezproxyberklee.flo.org/wiki/Cloud_Data