it is compatible with kaspersky free
nope, Kaspersky antiransomware is a lite version of kaspersky antivirus suites. They overlap each other
It has KSN (kaspersky cloud) and a lite version of System watcher (kaspersky's behavioral blocker)
this tool can block any type of malwares only if they are detected by KSN
however, when it's not detected, System watcher (lite) can only detect ransomwares and some trojans
I tested it in the past. It failed to block a lot of non-ransomware malwares. It's system watcher is noticeably weaker than Kaspersky AV's system watcher
it lacks signatures, full system watcher (can detect all types of malware), web filter, heuristics,...