As far as listing hybrid facilities goes - last time I played with Hybrids, there were so many facilities that if they were listed by planet in the Objectives tab, half or more of the planets in the galaxy would be listed. I don't know if it's still like that or not, but it's something to keep in mind if you want to add it in.
As far as the 'buy from trader' and 'flee from devourer' things go, don't the messages that pop up do more or less the same thing - the ones that say something like 'Zenith Trader visiting Someplanet' and 'Devourer Golem on Anotherplanet', that take you to the location when you click on them and show up in the upper left corner of the screen next to wave warnings? I see the objectives screen as a summary of long-term targets, not as something where transient conditions should show up - that's what the pop-up announcements are for.
I'd personally like to see something along the lines of 'Explore Nebula Wormhole on Randomplanet' if I have champions on. New capturables should also be added, and I don't think it'd be bad for the Dyson to show up there either.