A single user can lease up to two licenses to two separate workstations within a 24 hour period. An attempt to lease a third license in a 24 hour period will be revoked if the same User ID is used. Additionally, the existing license lease of the third machine, should there be one previously existing, will be revoked in the case where the same User ID has leased a license from two other workstations in the previous 24 hour period. The third machine will however be able to lease a license after 24 hours have passed.
This seems to work for me. I use this method when I need to do the odd bit of development of a document physically on the server - I have installed QV desktop on the server and can lease a licence using my network login credentials. In fact I've just checked and it is still leasing one from when I used it earlier this week.
Of course not. A named cal is tied to a named user. You cannot use 1 named cal for many (unnamed) users. Better get in touch with a Qlikview Sales representative to determine the optimal license mix for you.