I think we’re jumping the gun by decades here.

We'll first need to:
* check any spores for compatibility/similarity with Earth spores
* see what's available on other planets (do similar comparison if applicable)
* map currents in the Solar wind that would bolster/refute a "from Earth"/"from local life-harboring planet/moon/asteroid/comet" theory

Until we can crack physically the heliopause itself and take a hard sample of interstellar space, any life found in space would have to be local, and considered a kind of domestic breed.

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Yes to all the above.

So far, Voyager 1(!) and 2 are the only ones close enough, but unable to do so: "take a hard sample of interstellar space".

Marcia