This depends on the features you are using.
If you have HA enabled on the cluster, a VM will be started on an available host if a host failure occures.
If you have FT enabled on a VM, the VM will keep available if a host failure occures.
What happens to a VM without vmware-tools installed on a forced power off ESXi?
The same as for VMs with VMware Tools installed. Think of it, if the host gets powered off, all of the VMs on this host will die, and there's no other way as to restart them on remaining hosts. vMotion is a process of live migration, i.e. source, and target hosts have to be online.