I have Emsisoft Business on win10 VM and I like it. It is bloat free, fast too. Protection seems excellent, and support via online chat, not that you'll need it.
So, effectively it seems you would like to know which product can be installed alongside ESET Smart Security to complement its shortcomings?
Might I suggest @Andy Ful WHHLight could definitely be one
For Q1, KART is a standalone behavioral protection module(System Watch) of KFree (although it now can only block malware’s rather than deleting them in older version). So no need to install KART alongside KFree.