Can fake registrations like this actually result in counted votes? For example, could someone other than "Dick Smith" actually go to the polling place and say, "My name is Dick Smith", be matched up with the registration in that name, and cast a vote? Could a absentee ballot be cast in that name?
in states that do not require ID to vote, yes
Yes!. As long as he has somebody at that address willing to accept mail for him under that name, he's good to go!