The retro/wtf pattern is so loose it might as well not
really be a thing.
The only game it for sure occurred is Melee, when Sakurai included ICs for retro reasons and G&W for the typical wtf reasons (which typically was seen as a mix of retro/hardware/surprise). People thought the pattern continued with Brawl, given Pit and ROB, but while ROB fits the G&W archetype, Sakurai never explicitly stated Pit's inclusion was to represent the NES era again. He, unlike ICs, was a fairly popular request, so that could've played into the inclusion as well.
Then people tried to continue the pattern with 4, though it had already started to wither, given DHD might again fit the wtf archetype, but Little Mac, as he had already been revived, didn't fit the retro archetype. People also throw WFT in there, even though she's just a surprise character, which isn't really the same thing as G&W/ROB/DHD. And it definitely isn't the same as ICs or Pit.
And then there's no pretence of the pattern in Ultimate. There's a surprise character, but it's Piranha Plant, which only shares the surprise factor, and not the hardware, historical or retro connotations.
The only real pattern at this point is that Sakurai will sneak at least one surprise character on to the roster. Though this time it wasn't even in base. And Geno doesn't fit that archetype anyway, so it's all a bit tangential.
Well, Uprising was developed by Sora Ltd. and I'm fairly certain Sakurai was involved in its conception. I don't know when development began but the game came out in 2012 early in the 3DS life cycle. I don't think it's unreasonable to think Pit came about because of attempts to revive the series. After all Brawl showed off the redesign of Pit that translated almost identically to the main series games.
Of course Sakurai was involved, he directed the game. But the Brawl roster was created in 2005, and Uprising began, iirc, in 2009. However, initially Sakurai envisioned the gameplay, and toyed around with it being a Star Fox title before deciding that Kid Icarus fit better.
So given that at the beginning of Uprising, Sakurai didn't even know it would be a Kid Icarus game, I really doubt that four years prior such ideas were shaping the roster of a different game. According to him, the impetus behind Pit's redesign in Brawl was to modernize the character as if he had been receiving titles the entire time, a la Link and Samus.