My first attempt to list which of these I want most ended up being "all of them". In the interests of giving useful feedback, I think the most interesting ones are the problems with SETI (haven't heard anything about this but I also haven't been looking) and the origin of life (have heard about this but I suspect your post would be better than average).
Your response to CarlShulman makes me want more about eukaryotes too.
After many tribulations, my astrobiology bloggery is back up and running using Wordpress rather than Blogger because Blogger is completely unusable these days. I've taken the opportunity of the move to make better graphs for my old posts.
"The Solar System: Why Earth?"
https://thegreatatuin.wordpress.com/2016/10/03/the-solar-system-why-earth/
Here, I try to look at our own solar system and what the presence of only ONE known biosphere, here on Earth, tells us about life and perhaps more importantly what it does not. In particular, I explore what aspects of Earth make it special and I make the distinction between a big biosphere here on Earth that has utterly rebuilt the geochemistry and a smaller biosphere living off smaller amounts of energy that we probably would never notice elsewhere in our own solar system given the evidence at hand.
Commentary appreciated.
Previous works:
Space and Time, Part I
https://thegreatatuin.wordpress.com/2016/09/25/space-and-time-part-i
Space and Time, Part II
https://thegreatatuin.wordpress.com/2016/09/25/space-and-time-part-ii