1) If I understand correctly your question, you would like to have a list of all the slave site that are currently create from the front-end.
If this is the question, the answer is YES and this need to create a specific "layout" for JMS.
We have developed a layout that we called "List Anonymous" and that we hope publish before the end of this year.
You can already see it in action in the website
www.mywebsite2win.com
It provides a kind of directory with the list of slave site with their title and description.
2) Yes this is something that can be solved with the "partial user sharing" version 1.1.x that we will publish soon. We are currently writing the documentation.