The plan sounds pretty good,
For step 3 I am assuming you are referring to xvMotion, (change compute and storage at the same time)
Please check your vCenter is licensed for that feature.
You will need to check your EVC modes to ensure CPU compatibility and the ability to move the VMs from one cluster to the new cluster without power off...
Also I am assuming you are only changing ESXi Hosts and Storage hardware only, not vCenter (i.e. new appliance).
Kind regards,
vFouad