No, if you already started the maintenance mode in the ESXi. VMs will not be moved there or powered on by HA.
Anyways, I think that in this scenario, what you can do is Disable "Host Monitoring for HA". So you will ensure that no VM will be powered on if you loose one host for the power issuesTriple VCIX (CMA-NV-DCV) | vExpert | MCSE | CCNA
As soon as a host is asked to enter maintenance mode it is no longer a valid target for VMs within the cluster.