Good morning, if I understand. You have a 5.5 vSAN. You want to remove the SSDs and HDDs from those hosts and then physically move them to 6.0 vSAN hosts. You are then hoping the 6.0 hosts will see the existing data and you will be able to add VMs back into inventory.
If I have that right, that will not work. As soon as you go to claim the disks on the 6.0 vSAN hosts, you'll get an error that there are existing partitions and it won't claim them. vSAN will only claim empty disks.
Here's a risky way to do it. Let's say you have 3 node 5.5 and 3 node 6.0 connected to the same vCenter. You cold remove the SSD and HDD from a 5.5 host and move it to a 6.0 host. Configure those drives as local VMFS. vMotion the VMs to the one host. Now move the disks from the other 5.5 hosts to the 6.0 hosts. Wipe those drives and claim for vSAN on the 6.0 hosts. Set the vSAN data store to allow for reduced redundancy, vMotion the VMs to the vSAN datastore. Wipe the local VMFS drives clean and then claim them for vSAN.
Of course that would be crazy and you shouldn't do it 
Thank you, Zach.