I’ll just say that while I think most of the idea comes more from Kabbalism and Judaism read back into Mormonism there is more to 19th century views than you suggest Ardis. (The indirect claim about Eliza Snow by her brother, for instance) I find it completely wrong, of course. But I also think it goes well beyond what you suggest. That is more than what certain readings of the A/G theory suggest.

I know Geoff is a big proponent but it appears primarily based upon ethical concerns and concerns about strong libertarian free will such that a final judgment is even ontologically possible. (i.e. a final judgments suggests an essential character)

Those attempting proof texts though tend to try and find plural uses of the term “probation” (often in late secondary “recollections” of things Joseph Smith said). They then take the extra step of arguing this entails reincarnation which seems dubious logic at best. After all it can easily be interpreted to mean that everyone after judgment continues to progress and that progression is a new probation but not a new mortal life. (i.e. the rejection that you are immediately exalted at resurrection with no progression or learning or grades)

Typically talk of MMP tends to conflate lots of different issues though – especially when engaging in proof texts. (IMO)

GQC appears here to be familiar with the idea only as a perversion of the gospel, not as something that had ever been taught by even some of the leaders.

However, something imbedded in this particular question made me look at the issue in another light, too. Specifically, the question is asked about a suicide that occurred in the throes of some highly emotionally-charged situation. The thought occurred to me that, in the law, we generally take into account the killer’s state of mind, i.e, whether some event caused such rage or terror that they were left without the ability to to objectively evaluate their actions. And that it’s pretty much settled that the severity of a taking of life can be somewhat mitigated by these extenuating circumstances related to the offender’s emotional state. So, too, these extenuating circumstances related to one’s emotional state – and not necessarily related to mental illness – should also play into our understanding of how to evaluate a suicide.

Maybe I’m stating the obvious, but the question as posed in this Q&A made me think about it from this angle.

Here is the bit on Heber J. Grant and water.