This is what I’m assuming.
[quote=“DrForrester, post:119, topic:712074”]
We know that Tuco & The Twins are cousins. But, do we have any other relationships explicitly given? I see (above) the suggestion that Tio is Tuco’s uncle, rather than his grandfather. Do we know this to be the case?
Why would he call him Tio, then, not abuelo? No, he’s not Tuco’s grandfather. We don’t know if he’s an uncle or great uncle, but uncle he is.
I thought that Tio was his name rather than his title. I don’t speak Spanish. But, I see after a little googling, that his character’s name is Hector Salamanca. A thousand apologies. That’s why we have these little conversations. 
There was also the change in hair-density: sparse in the Cinnabon-era scenes, and lush in the six-years-earlier scenes. (Gilligan had a top-of-the-head shot of Saul/Jimmy in the Nebraska part to make it clear.)
According to wiki, Hector is uncle to both Tuco & The Twins.
http://breakingbad.wikia.com/wiki/Hector_"Tio"_Salamanca
This sets up Abuelita as mother to Hector - which I find implausible.
Why implausible?
Abuelita is a term of affection basically meaning “little Grandmother”. She appears to be in the same generation as Hector so if there’s a family connection then it would most likely be sibling.
I’d argue they look about the same age. Although a stroke can age you a lot in a short time, and isn’t that why Hector is (was? will be?) in a wheelchair and has to talk with a bell?
Work release job from whatever crime he committed that got him booted from the force in the first place?
Implausible because of their relative ages.
Miriam Colon (Abuelita) was born on August 20, 1936
Mark Margolis (Hector) was born November 26, 1939
Even forgiving the timeline change and the possibility that it could’ve been a pregnancy very early in her life, I still think it’s much more plausible that they have a Brother-Sister or a Husband-Wife relationship. Making them Mother-Son is uncomfortable.
That’s the ages of the actors; it doesn’t relate, necessarily, to the ages of the characters they are playing, which depends on how they are portrayed with makeup etc: and It is difficult to tell “in universe” the relative ages of a stroke victim and a non-stroke victim (both being relatively elderly).
They could also be from different sides of the family, or a step-mom/step-son relationship. You’re right that Abuelita being Hector’s biological mom is a stretch. I still think they could both believably be Tuco’s grandmother and uncle though.
I don’t agree with the sentiment that Jimmy running into Tuco is too much of a coincidence. Tuco is a big wig in the local meth trade (or at least will be by the time of BB). Jimmy running into him and Nacho will presumably be what gets Jimmy involved with people in the meth trade. Jesse is also involved in the business so it makes perfect sense that he would have knowledge of both of them.
Just in case anyone missed it:
Abuelita is a title. It translates to “little grandmother”. Abuela is grandmother. Calling an older woman (related or not) would be the same as calling her Granny or Nana.
Tio is a title. It means Uncle. You might also call a close family friend Tio.
In this case, it seems Tuco is related to both of them, but we have no real reason to believe his grandmother and his uncle are related at this point. One could be related on his mother’s side and the other on his father’s.
Clearly I am thinking about this way too much.
He’s obviously related to Hector Salamanca on his father’s side because of the traditional same last name thing. His grandmother doesn’t have a name. She’s just listed as “abuelita” so unless they actually give her a name we won’t know for sure.
Saul has the phone number now. We may see Saul’s fortunes take a serious dive to the point that he calls, or perhaps Tuco may need a lawyer and make Saul an offer he can’t refuse.
In universe, the chance of the skate scammers running into Tuco’s elderly grandmother because she’s driving a similar car as their real target and then following her home because she does a hit and run is absurdly improbable. The Doylist explanation you offer explains why it happened, but just makes it all the more transparent. Yeah, the entire point was to hook Saul up with the criminal underground and allow him to show off his lawyer skills in the desert. Instead of helping some low level thugs he gets involved with the kingpin in the second episode by pure chance!
BB had plenty of wild coincidences, and Tuco is cool in my book. Just gotta recognize the flaws. I imagine someone who never saw BB would be super confused re: Tuco right now.
If this hadn’t happened then Walt would presumably have ended up with a different lawyer who had his own back story. There’s nothing coincidental about it.
You’re basically saying “what are the odds that someone he’s involved with later was someone he ran into earlier”. He wouldn’t have been involved if he hadn’t run into him earlier. There’s nothing coincidental about it. It just seems that way because we’re seeing things out of order.
Suppose we had seen the story in order:
[ul]
[li]Saul meets Tuco through happenstance[/li][li]Because of that, Saul becomes involved with people involved in the meth trade[/li][li]Later, because of his reputation amongst people in the meth trade, he meets someone (Walt) who is also in the meth trade and has also been involved with Tuco.[/li][/ul]
Does that seem overly coincidental? To me it’s just a series of events who’s connections are totally unremarkable.
Saul also has extensive experience in money laundering in Breaking Bad, so at some point he would almost have to be involved with high-level drug dealers.
I agree - this is sorta similar to the “Texan sharpshooter”: the guy who blasts away at the side of a barn and then goes up and draws a target around the bullet-holes. 
Stuff that happened sure looks improbable in hindsight!