A common fan nickname for alternate universe Walter was "Walternate." Guess what Walter calls him as of episode "Peter."
Altivia, Bolivia, Fauxlivia, or, to some especially uncharitable Peter/Olivia shippers, Holivia. It's worth noting that the fans are fiercely divided on which Fan Nickname to use. The series has decided on 'Bolivia'. Walter has decided on Fauxlivia, however.
And now there's Belivia. Really.
Charlnate (or Scarlie) and Lincolnate - though who the latter refers to is a source of debate among the fandom, since Lincoln is a much more prominent character in the alt universe. Some people have taking to referring to the Lincoln on "our" side as 'Kennedy', since Walter called him that once.
Madeline from The Plateau is going to be Abigail Hobbs from Hannibal.
And of course Gríma Wormtongue is playing a villain as usual when he makes a brief appearance as a bioterrorist working with Walternate in the season 3 finale.
Network to the Rescue: Season 4 saw a mild drop in critical acclaim and a large drop in viewers, essentially spelling the end of the show, ESPECIALLY since it was on Fox...right? Wrong! Fox renewed it for a 13 episode fifth and final season instead to let them finish up their story, and bring the episode number up to 100 so that it could be syndicated.