Palgia,
Q1. It is definately NOT safe to assume that ALL airliners are equipped with this technology. Of the 7 jets I've flown in airline service, only 2 had such a system. That doesn't mean that manufacturers haven't back modded older aircraft. 411A, did Lockheed produce the L1011 with this system, or was it a back mod?
Q2. Of the 2 aircraft that I know, there is an EICAS message to advise of icing (even if the message only advises that it has automatically turned the Anti-Ice equipment ON).
Q3. None that I know of, but, all the older Boeings that I flew used ice accretion on the 'large lumpy and ugly' windshield wiper bolt as a good indicator.
Q4. Conventional theory does indicate that sharper objects do accumulate ice more quickly, but, refer back to Q3 regarding 'large lumpy and ugly' windshield wiper bolts.