My .02...
You mention you are relatively inexperienced with handguns so I would lean a bit toward compact rather than micro. If/when time comes to save your bacon, the micro guns are harder to shoot well, sometimes even for experienced shooters. You have more than enough choices in compact handguns to choose from, depending on your preference. As you already mentioned, thoroughly research the difference between SA, DA, SA/DA, striker, hammer fired, etc. There are pros and cons of each. Do you want a manual safety or no?
I personally prefer no less than 9mm. Yeah, "Shot Placement is King," but in calibers where you trade expansion for penetration or vice versa, that mantra is more than a canned response. You decide for yourself, though, after you've done your homework.
Good luck.