You are right about supernova hampering life evolution, but it's unclear how long the fireworks lasted. In my comment I argued that it is possible to have the conditions of life emerge much earlier than 13.5 billion years. Not that it necessarily happened.
Regarding the second point have a look at https://www.ligo.org/science/Publication-GW170817Kilonova/in... . That isn't my field of specialization, so I am not sure about recent publications. At the time though this was a big deal as kilonovas seem to be the primary source of heavy nuclei in the universe. That particular event crested between 1/100th to 1/1000th solar masses worth of heavy ( heavier than iron) nuclei. This is a greater rate than supernovas estimations.
Regarding the second point have a look at https://www.ligo.org/science/Publication-GW170817Kilonova/in... . That isn't my field of specialization, so I am not sure about recent publications. At the time though this was a big deal as kilonovas seem to be the primary source of heavy nuclei in the universe. That particular event crested between 1/100th to 1/1000th solar masses worth of heavy ( heavier than iron) nuclei. This is a greater rate than supernovas estimations.