1 The antivirus programs for Linux do not provide real-time protection. It is not like AV for Windows. AV for Linux is only for periodic scans of your system (or for scanning your Windows installation). So AV is totally optional, and there are no tests to tell you which ones are any good.
2 Enable firewall.
3 Use the software from your distro's repository. It's safe. If you need to install software from another source, check it out well, because once you enter your sudo password, nothing is protecting your system from infection.
Ubuntu, and therefore its forks such as Mint, have big repositories. I tried a Debian-based distro called MXLinux and I couldn't get the packages I needed for my software. Depending on your software needs, you might have to compile some packages yourself. So if you want to keep things easy, choose a distro such as Mint.
4 Do your daily computing in a standard user account, not an admin account.
5 All the advanced security tools for Linux are unnecessary for the average user. Linux home users do not get infected. If you are running a large server, then you are a target, and you need to worry about security.
6 Read Linux news every once in a while, so you know if there are any issues.