2 quick winter questions

First off, sorry to be that guy asking stupid winterizing questions, but I'm getting it done this weekend but have had it in 32 degree temps twice this week (where it was probably that cold for like an hour or so). How likely is it that my engine was damaged?

Also, my boat will be outdoors all winter with my factory boat cover on it. Should I also put like a tarp or something else over too?

If it's any help, I live in a desert climate in southern CA and I have a Malibu. Thanks a lot in advance!