I wanted to make a post on this but I think you've already nailed the question so I'll just add my thoughts here.
Imo, I think it's become clear now that Shanks was at least talking to the Gorosei about Luffy and not another pirate. When you "thematically" place scenes from before and during Wano, the purpose of that scene seems to have been used to drive what we see in 1037. We unironically do not see the Gorosei again after chapter 908, discussing a different topic (Cobra), not until 1037 at least.
I'm gonna walk through my thought process here:
- Post timeskip, Shanks is not seen for literally 300+ chapters outside of a cover story (celebrating a Luffy bounty raise no less lol). He's never shown in real time since Marineford.
- In chapter 903, the first time we see Shanks post-timeskip in chapter content, hes looking VERY competitively at Luffy's 1.5 Billion bounty poster.
- In chapter 907, we see Shanks talking to the Gorosei. Thing about the timing of this conversation. It only happens AFTER he sees Luffy's poster.
- Oda does a very weird literally technique (imo, not a good one) where he'll have a character randomly talk about a topic unrelated to them, without a lack of foresight. There see multiple examples of this, but there are 2 in Onigashima's battle. One is when the CP-0 member randomly brings up the idea of Vegapunk's artificial DF being missing from PH and "shivering" at the idea that a second dragon could exist. This literally was a forced foreshadow on Momo growing big and making a big entrance, however it was "unknown" to the reader at the time that Oda would do this unless theorized. The 2nd one, imo, was Who's Who talking about Luffy, Shanks, the Gum Gum fruit and Sun God Nika. WsW is the ONLY Beast Pirate Member who is a former WG employee. Coincidentally, he's the only fight where exposition is delivered that is unrrelated to their fight. King remembers Kaido wanting to be Joyboy and rescuing him, but it ties to Zoro and him both believing in their captains. WsW here literally talks about how he bears a grudge on Shanks for stealing the fruit, which has literally nothing to do with anything. Even Sun God Nika is a weird lore dump. Yes, it's tied to him mouthing off about slavery, which pisses Jinbe off, but the ACTUAL topic is very random....unless it's not (i.e. recent events).
- In 1037, the Gorosei talk about some hidden devil fruit with a different name. Context, once again like the above, is seemingly forced because the reader has NO idea what this is supposed to mean, not until its elaborated on. The biggest piece of news here is that they clearly did not know this beforehand (or at least did not know there was a connection between what they know and Luffy/Zunisha), they even ask why the WG hid the name. This is a question they also want answered. Hence, someone fed this info to them recently and they are still deliberating on it.
- 1041 then confirms that the goal that Rob Lucci relayed to them 13-14 chapters prior (capture/kill Robin) is being overshadowed by the Gorosei wanting Luffy dead. This is an IMMEDIATE change based on Zunisha arriving.
- Dialogue between the CP-0 members here implies that they are killing him as a preventative measure, "its all rumors and heresay". I.e., this means the Gorosei were told something that they did not truly "believe" until the Elephant arrived at Wano.
- The Gorosei have uttered not a word about Luffy and his powers. Not in 1000 chapters of One Piece. Sure, his annoyance as a D. Clan member, but nothing on the level of "HE MUST DIE NOW". Again, shows that there's been a major goal shift the moment Zunisha showed up.
- Finally 1043 confirms that whatever fruit they were talking about, whatever awakening it might be, is hidden under the guise of the Gum Gum fruit, effectively tying all of this together.
So essentially, it seems Shanks stole the fruit, knowing it's purpose. Found out about Luffy (or Ace?
@HA001 made a good point the other day that maybe Luffy was never part of the plan, but Ace was) at Fushia. There Luffy, the idiot, destined himself into eating that fruit.
By this point Shanks rolled with it and became friends with Luffy, making sure he survived as a kid and "gambling" his arm on watching him grow, with the
intended goal of him becoming an exemplary pirate to save the world because its his "destiny"......right??????
However there are now two things that seemingly contradict this.
1. Shanks never went to Laugh Tale. In Roger's flashback, it was made excruciatingly clear that he and Buggy do not know where it is and will go on their own. Oden sees Roger tell Shanks something, but does not hear it. Imo, it was not about said prophecy and Laugh Tale, but something related to Shanks and his motivations. If it was about the former, i think Oda would have made it clear (just like I believe that if Shanks were talking about Blackbeard, Oda would have made it obvious instead of just saying "a certain pirate".
2. Shanks even telling the Gorosei something (i.e. warning them/letting them know facts about Luffy or what he did) is extremely red flaggish. The fact that he can just go there to speak with them is already weird in of it self. It shows he's not really against them (at least not outwardly like Luffy would be). If he wanted Luffy to directly succeed with no issues, why tell them anything? Why feed the enemy information like this? Sure, it could be to service Joyboy's return, but again, Shanks should not know about most of Laugh Tale.
In my opinion, Shanks is a 3rd party with separate motives, working on neither side to service his own direct goals. He wanted Luffy (or Ace?) to become Joyboy and fight the WG, but he is purposefully setting them on a collision course before Luffy even becomes PK. Why, if destiny is meant to be fulfilled, would he need to influence the WG into doing this? Why not let "destiny" resolve itself anyway.
So the main questions (to me) are:
- How did Shanks come upon this information?
- WHY is Shanks doing this in the first place?
What does Shanks gain out of this? Surely, we will find out soon, as Oda has been hyping up his character recently, especially with the film being made. I'm sure he cares about Luffy. I'm sure he's not "EVIL". But something is definitely up with him, and not in a good way
@Tyki_Mikk @Bounty @Sentinel
curious about some opinions 
