You can update the size of the cache that AVA-v uses. First, shut down the AltaVault appliance using the Maintenance > Shut down screen. From VMware, then edit the VM and modify the 2nd disk to the new size 200GB in this case). Note: the disk is the one you added during the deployment of AVA-v from the template, and is not the first disk (the AVA operating system disk). Once done expanding the disk, you can boot AVA-v, and it should detect the new size properly.
The cloud consistency error seems to be something else entirely and not related to the disk - perhaps something tied to you not cleanly shutting down the AVA-v VM while operations were ongoing with the cloud. Assuming this is a test environment, I'd suggest starting over from a data standpoint. From AVA-v command line after the VM boots (connect to the command line via an SSH session), you can issue the following:
no service enable
datastore format all (note: this wipes the cloud and cache of data, and assumes the cache expansion issue is resolved per above)
logging files rotation force