I had the same feeling about 'Seelenfreund.' I doubt there's enough evidence that it's really an established word, but if it's entered at all, I suspect that it actually ought to be translated as 'spiritual friend' or something more specifically religious. Anyone who wants to add it in LEO needs to find more actual definitions and examples.
I disagree, though, with the original suggestion for 'soulmate'; or at least, surely that should not be listed as the primary or only sense.
The basic, original meaning of 'soulmate' is the same as 'Seelenverwandter' (kindred spirit) -- that is, not necessarily anything to do with romance, only with close affinity. There are surely earlier examples where two children, two close friends, even two people who simply share the same (possibly crotchety) outlook but hardly know each other, are described as soulmates.
It is now occasionally also used in a context where you could translate it as 'Traumpartner' (ideal partner, ideal mate), but I suspect that's often just a coincidence, when someone's spouse or romantic partner also happens to be a true kindred spirit. (Which is not by any means always the case; think of 'opposites attract.') Otherwise, it may sometimes simply be a misunderstanding arising from too modernized or too American a reading of the word 'mate.' In fact, at root and still in BE, 'mate' means simply companion, but not necessarily spouse. So the compound is essentially of the same kind as words like roommate, teammate, classmate, and so on.