1: You will create a new snapshot every time you need to update the image so it's not a problem to create multiple snapshots.
2: Here is a VDI calculator that will assist with a lot of different VDI scenerios and calculations, http://myvirtualcloud.net/?p=4920
3: It is a common strategy to place the replica on SSD. It doesn't have to be on the same LUN as the clones.
4: It's all about uses cases and if your use case dictates you need persistent desktops then you should use them. If you want storage savings you can use linked clones but they will have to be refreshed and recomposed at some point no matter what.
5: rebalance is the process of moving linked clone desktops to new storage locations
refresh is the process of reverting the clone back to the current image
recompose is the process of changing the desktop to a new image.
In your chart the linked clone VMs don't have to be in SSD. If you have enough SSD than that's fine but from a storage workload most of the IO happens on the replica. You should deploy a small test and monitor the IO footprint to see if that remains true for your environment.
