This will vary by airline, and by market. Generally not, since recorded locators are usually difficult to remember. However, this may vary with individual airline policies. If curbside stations have automation, the skycaps will verify that the passenger has an E-Ticket and check baggage. Provided they are not checking luggage, travelers may proceed directly to the gate for check in and to obtain boarding passes.
Procedures vary by airport.
Some airports simply require passengers to identify themselves to security personnel as E-Ticket passengers. Passengers my be checked in manually from this list and have their E-Tickets updated later. Boarding passes for all connecting flights will be issued at first point of check in. Airlines are working to develop standards to eliminate this intermediate step. Yes, just like paper ticket, upgrade certificates or banked miles will be surrendered at time of check in.