In the first season, did Liz have any relatives other than her parents and Grandmother? Maria just her mother and absent dad? I know Isabel mentioned grandparents or at least a grandmother in "Leaving Normal" - any other relatives? I know Michelle Valenti was mentioned in season 1 and so were Alex's parents and we saw his dad.
Maria also mentions a grandmother in Wipeout, and in Summer of '47 she mentions that Hal reminds her of Breepa Deluca. I am guessing he is probably her grandfather.
There was Pete Parker in the Summer of '47. He must have been one of Liz's great grandfathers.
Kyle also mentions his grandmother (Jim's mother). And I can't remember what episode, but there is mention of a grandfather for Isabel and Max.
I've seen some timeline sites, but, within a first season episode do we get any dates mentioned or shown onscreen for any episode post-Independence Day?
I have a very extensive timeline on my website will all the dates that were mentioned, shown, or I have been able to figure out based on things that happened in the show.
http://www.roswelloracle.com/seriestime.html
I'm very fond of the idea that Nasedo (as named by River Dog), Pill-popping shapeshifter, and Ed Harding are not all three the same person. Harding and Pill Popper have very different MOs. Harding leaves bodies everywhere, enjoys the game with Liz, blows up a gas station, etc. Pill Popper is subtle in directing Michael home, makes sure the paperwork with Hank is cleared up, buries the body, etc. Plus he puts on a show when he transforms. I do think the writers intended them to be the same when they introduced Harding, but I like the idea that Harding was the one that escaped, and Pill Popper/TicTac was the one that took a while to get away (for a AU-post-Destiny story). That said, why did Pill Popper, whether or not he's Harding, pose as the Doctor and say Topolsky was crazy (and then he didn't do anything to eliminate her, right - that was Pierce)?
I have always believed that Ed Harding and TicTac were different people, and it is not clear which one was Nasedo. It was never clearly explained on the show, but there is some 'evidence' that they were different people, and you're observations are part of it.
My friend (who goes by the name of River Dog) has some reasons why we believe they are two different people -
1. Nasedo is never seen eating Tic Tacs when he shapeshifts.
2. Tic Tac shapeshifts mostly to blue light, Nasedo shapeshifts mostly to yellow light.
3. Shapeshifting takes longer for Tic Tac.
4. Shapeshifting appears to take it's toll on Tic Tac, Nasedo has no trouble.
5. Nasedo gets directly involved with the gang, Tic Tac is more behind the scenes watching them and even appears suspicious at times.
TicTac
I believe that TicTac was the Watcher or Guardian of the Orb, as some people call him, who watched over Max and Liz in Sexual Healing when they found the orb, as well as the one who killed Hank. He was probably Dr. Margolin too, who stopped the kids from meeting Topolsky and falling into Pierce's trap, not to mention that he gave the Sheriff the plausable explanation that Topolsky was insane and fixated on the kids and never worked for the FBI.
TicTac is careful to blend in, taking the form of drifters or locals that you wouldn't really notice. He is low-key, staying mostly in the background. He covers his tracks, making sure to get rid of Hank's body and taking care of the legal side of Michael's foster situation before making it look like Hank left town.
Ed Harding
But Ed is definately not low key. He has left a trail of bodies all over the southwest, as Hubble says. Tess also mentions that they have been hunted for years by the Special Unit. How could that happen, unless Ed was doing stuff to lead the Specail Unit to them?
Ed seems to be a loose cannon. He is cocky, acts creepy and seems to enjoy scaring the kids, leaving mysterious alien symbols and taking Liz, and he challenges the Sheriff and Max. Why wouldn't he just tell them who he is when he came to town?
He kills a Special Unit agent and leaves him on the side of the road for Pierce, blows up a gas station, and sends an alien signal all while wearing Max's face, and makes sure to be caught on camera to lure Pierce into a trap.
When he replaces Pierce, he leaves Tess (a minor) alone and doesn't make any plans for her protection.
And what about the Dupes protector? According to Ava's drawings from the SHP, their protector left. So it is possible that TicTac was their protector, and left them to keep watch on the 'real' royal four, or possibly there is another shapeshifter out there. (I personally try not to think about season 3, because I hated it so much, so in my mind Kal doesn't exist.)
There is more about this on my website too if you are interested -
http://www.roswelloracle.com/theoriesshapeshifter.html