1/ It is safe when I will have VCSA on cluster with 4 ESXi? But what will do e.g. live motion in HA when host with VCSA will fail? Fix me, but this do vCenter and must be online, no?
Your assumption that the vCenter/VCSA needs to be online for HA to function is incorrect. You only need a connection for the inital configuration of the HA agents on your hosts.
If the host running the VCSA/vCenter VM fails, HA will save the day as usual by restarting it on another host, just like any other VM. The HA restart process has nothing to do with live migration/vMotion either (which would require vCenter).
So if you have the choice between a standalone host with whatever hypervisor and a fully redundant cluster with HA and live migration, which is the better choice for hosting the VCSA VM should be pretty obvious.
2/ It is hyper-v appliance somewhere?
No, there is no Hyper-V VCSA appliance.