Need to validfate my App design based on CouchDB & PouchDB

needless to say I am still learning and have a long way to go…

I am working on a app with CouchDB & PouchDB, I just wanted to check what was your experience with similar setup ?
in my requirement app need to be capable to work in offline mode on most of the time, once connected should be able to sync data back to CouchDB server.
I am going to have around 100 users working on the app at the same time, not sure how couchDB server going to handle the load ? do I need to plan anything for this ?
Another challenge I have is I am going to use CouchDB for authentication, but CouchDB doesnt have service to reset the user password, have anyone else used CouchDB for auth or I should be looking into MangoDB etc ?