It doesn’t force memory into cache directly. It determines values of bytes in memory by using the byte as a multiplier to an offset in memory. To determine byte value you can check all the offset combinations to see which was cached. Details in the meltdown paper.
I also switched from two monitors to one a few months ago. Main reason was I wanted to eventually switch to a standing desk and one monitor was going to make that easier. Also, when I work remote I can just use my laptop's screen and not be used to that second monitor.
Spam malware can scan IPs to find open SMTP ports to send spam so some ISPs and hosting providers lock down these ports to avoid getting their IPs blacklisted when a compromised host starts sending a bunch of spam through an open relay. I can see this being used to send email out from some restricted hosting providers.
I'm embarrassed to say it took me a full year of mac use (I came from linux originally) to learn that preview app could edit as well you can insert your own signature!