chickeness

It just came to me that Hoid and Preservation's plans had to be different, because Preservation intended for Vin to take up the power in the well of ascension, while Hoid didn't try to contact her beforehand or even in the Well to tell her to take up the power.

This came when Kelsier was in the Well of Ascension, and I'm fairly certain, based on both Preservation's and Hoid's reactions, that Kelsier wasn't a part of the plan beyond his death- him not going Beyond led to their plans succeeding, yes, but that wasn't intended. Preservation's plan was that Vin take up the power in the Well(at least the plan of the remnant), which could mean Hoid's plan by the time Vin was at the Well had moved to Kelsier taking up the power- but I don't see how he could have known a ruin-influenced cognitive shadow could've taken up the power of Preservation, only after the Well was emptied.

You need a slight amount of allomantic ability to be snapped by the mists- and there needed to be a way for it to be originally introduced to the population of Scadrial. I'm guessing a a bead here and there every thousand years, with no breeding programs, and a much rarer abuse of children would have allowed for the low level of allomantic abilities pre-TLR. It's possible Preservation gave everyone a background ability to use allomancy- but I don't think he would've spent more power than was required in the creation of humanity.

Hoid is no stranger to overarching plans- his presence on Roshar is for one, a single, Stormlight-related plot goal. He is confirmed to possess a plan, when in Secret History, Hoid says to Kelsier: Neither Leras or Khriss give hints away, other than that Khriss considers her task futile when she hears he took the second to last Lerasium bead- but Hoid's search of adding new magic systems to his portfolio always seems secondary. Other than the theft of the lerasium, we know three things Hoid was doing during era 1. The first is that Hoid was a successful informant in Luthadel during TFE, one known to both the nobility and rebellion, who dealt with both, and was successful enough he was smoking tobacco, a high-in-demand luxury item on Scadrial. The only thing that seems notable here is that Hoid either doesn't know about House Renoux being a front of the rebellion, or he's trying to dissuade Kelsier in the guise of a nobleman from peering too closely into Renoux. The second, during WoA, is that he is primarily in Terris, not trying to get Feruchemy, but investigating it, because he has a power that is similar to Feruchemy, and he is attempting to secure guidance from the Synod and the Keepers. With the Razing of Tathingdwen, he ends up wrapped up in the event, and becomes the leader of a group of Terris refugees, securing their safety. The third, during HoA, is that he is doing the successful informant thing again, in Fadrex City- successful enough that the King of the Dominance, Ashweather Cett, encouraged Vin to seek him out for information, but the two never meet, as Kelsier guides her away from Hoid, and Ruin is unaware of his presence in Fadrex. Now, what was this plan? The biggest thing Kelsier did was overthrow the Final Empire, and pave the way for the death of the Lord Ruler- so Hoid was planning for him to die- but for what reason? I've seen speculation that the plan was to grab the lerasium and run, but if this was true, then Hoid would get the hell off of Scadrial, as opposed to sticking around after the Well of Ascension is emptied and there are no viable ways of getting off world. Hoid knew Scadrial would survive, and stayed on the world until the Catacendre. Leras states that he and Hoid were not in contact in the past few years, so Hoid possibly doesn't know Preservation's plan, but he has been on Scadrial before- the Terris Worldbringers was either founded by Hoid or someone influenced by Hoid. It's possible his plan was Preservation's plan, and he was aiding him secretly- and that seems the closest, but Kelsier was integral to the success of Preservation's plan, so why was he ignored by Hoid? Pre-Roshar, being a subtle actor is what Hoid's best at, and I have no doubt he used this to nudge rumors and people towards certain actions, and this made up a majority of his subtle influence on his world, but I am clueless about his ultimate plan- other than it does not involve the destruction of Scadrial.

IIRC, Sanderson has confirmed there were past users of the Well of Ascension- it's possible that the remaining 5 beads could've been used by past users of the Well. After all, Allomancy was present before the ascension of TLR, although it's up in the air whether Preservation created humanity with allomantic abilities or not.