1. This extension blocks javascript per site requests, yes this break websites but this is something you can whitelist per script on a site which Scriptsafe remembers next time you visit a site. It can also stop iFrame malware infections, blocks exploits hosted on malicious sites, built-in fingerprint detection over various methods, removes web bugs, removes Google Analytic UTM Tracking, unwanted content, ad networks and a whole lot more. All this without slowing your browsing down too.
2. Would be ideal to utilise in my opinion.
3. I have not had any trouble with the Malwarebytes version and a new release was issued about 2-3 days back, just set MWFC to Medium Filtering and turn on Notifications you should have nothing to worry about, the Notifications gives you a fab look at the IP address, port and tells you if the outbound connection has a verified Digital Signature helping you with an informed decision.
~LDogg