You're forgetting option 3, and IMHO the most likely option. We become a space native species that inhabit an armada of ships. Colonizing planets beyond mars

You're forgetting option 3, and IMHO the most likely option. We become a space native species that inhabit an armada of ships. Colonizing planets beyond mars will very much be a secondary, optional objective. I think in a millennia, the number of humans living in o'neil cylinders will far outnumber the humans living on planets.