Well, as a professional logician (retired) and mainly as a persistent buttinsky, I have to say a few things about all of this. First, thanks for the citation; I hadn't heard that one for a while and it is nice to see it coming round again.
I am curious about why 'mije soweli' rather than 'soweli mije,' "beastly male" rather than "male beast," not to mention why 'soweli' rather than 'jan,' the general term for hominids.
'kepeken e luka sama,' just to confuse things thoroughly, 'kepeken,' as a verb, takes the instrument as direct object, not as complement (object of the preposition).
'ni la' is pretty clear, 'oko la' less so. One moves toward "obviously" or "apparently" or maybe even "it is easy to see that"
What jan Ote says about 'olin,' though I doubt whether it will survive, given mainly English speakers in the community.
All the "a"s and "b"s mix apples and oranges, so that it is hard to dig out the point. So, given a, b as sentences, 'a la b' means "if/when a, then b." Given that a, b refer somehow to events, 'b tan a' means "b because of a" (assuming, in addition, that this is all grammatical). Under this latter assumption, with b now a sentence, I suppose, and a a noun phrase, 'tan a la b' means "Because of a, b." It is not a pleonasm, because a has to be something that actually occurs (all the usual caveats) whereas, in 'a la b," a need not occur (or, indeed, even be possible), but IF/WHEN it does, then b does (b also has to occur in the 'a la b' case (usual caveats).) 'a la b tan a" is also not a pleonasm, since it adds the information that when b occurs upon a, it also occurs because of a, which is notma given (cf. post hoc ergo propter hoc is a fallacy). jan Ote, quoting me, has the rationale for at least the different placements of 'tan ni' covered. For other a than 'ni' it is harder to explain and I have to fall back on individual preferences, since most such cases seem to work either way (but there is a lot of work to be done on 'la' yet). I don't understand case 6 at all unless we are into causal strings, which I try to avoid for sanity sake.
Sure, any word that referes to something that can be a cause or source of something (and I suspect that is just about any content word) can come after 'tan,' a perfectly normal preposition. The 'tan ni' forms are just stressed because they tell how to deal with a common English situation, "because" as a conjunction, which tp treats differently.
There are no places to put sentences aside from: all alone, before 'la', after ' ... la,' and after 'o'. Any place else English might tempt you to put them has to be worked around somehow, usually involving 'ni' (cf "that" in English).