As I say, I read the Pali Canon because it's useful and well written. Period. Ok, ok, I make my fair share of the mistakes explained above, I like the idea of sitting zazen in Japanese Water Gardens and part of me probably thinks that's enlightenment, but I'm learning, like at Christmas when you learn it's not about the presents, but you still give them.
As to luminous minds:
Luminous mind (also, "brightly shining mind," "brightly shining citta") (Pali, pabhassara citta) is a term attributed to the Buddha in the Nikayas. The mind (citta) is said to be "luminous" whether or not it is tainted by mental defilements.
The statement is given no direct doctrinal explanation in the Pali discourses, but later Buddhist schools explained it using various concepts developed by them.
I don't explain it by developing concepts - I recognise it as true. I have no real faith in the logic or systems developed by any Buddhist School whatsoever. I regard logical systems ultimately as a category mistake, though useful at times e.g. if you're doing calculus. I regard Buddha's teachings as teachings, meant to be realised and not extrapolated and made to jump through ludicrous hoop arrangements just to reassure the mind which is afraid that the world doesn't make sense on its terms. Apologies for including another poem, but they do explain things better than prose sometimes.
A soldier is lost in a library. Between page and eye
birds are forming from coloured honey.
The soldier thinks there are so many answers, but mine must be
the prettiest. The birds are fountains that swallow themselves.
They are all liars, but they sing well and pretend
they exist and are sane. The soldier juggles with them,
clings to them, entreats them,
wrings them till they spill
ink over continents, thinks
that if they are mad then the world is mad.
The birds shed themselves empty.
The answers are not colours and sweetness, the soldier
is pleading, is pleading, is pleading.
Although an enlightened individual's consciousness is a karmic result, it is not limited by usual samsaric constraints. The Buddha discusses in the context of nirvana a kind of consciousness described as:
Consciousness without feature, without end, luminous all around.
This "consciousness without surface" differs from the kinds of consciousness associated to the six sense media, which have a "surface" that they fall upon and arise in response to. In a liberated individual it is directly known, without intermediary, free from any dependence on conditions at all. According to Peter Harvey, the early texts are ambivalent as to whether or not the term "consciousness" is accurate. In one interpretation, the "luminous consciousness" is identical with nirvana.
So there is support for my statement.
Maybe what I say doesn't accord with the view of a monolothic 'Theravada' as you refer to it, though I think I've shown that my view is one accepted interpretation, but I read the passage in the sutra and I know what's being referred to, because that's the experience I've had of my mind. Also in the other, negative, quotes about mind you provided, Buddha was talking about mental processes, thoughts, which can indeed be all the negative things detailed. In the luminous quote Buddha is talking about unconditioned mind, which is not just a mental process but everything experienced (is mind).