Good idea, assuming you're referring to using only one at a time but at different periods in time.I have kaspersky key till June eset till Feb 2019 and emsisoft till December so I can use all
The Windows Firewall didn't changed much since Win7, it is solid enough for classic users. It was only weak on XP.The firewall is the one that decides many times the difference between something good or something very good and I am not comfortable with the Windows firewall in previous editions.
did you submit the files?Emsisoft detects a lot of false positives, and at times, its behavior blocker will automatically quarantine a file. In my case, it once quarantined an important file and later I was unable to restore it causing a big mess for me.