How will ESX handle Virtual Provisioned LUN

I created several thin LUNs from VMAX for VMware ESX host because I want to test FAST VP. After adding these LUNs to ESX storage group, some questions arised on how VMware handle thin LUNs.

1. If VASA is not configured, will ESX be aware of this is a thin LUN not? My guess is no.

2. If ESX doesn't know it's thin LUN, will VMFS datastore creation allocate all space of the thin device? My guess is yes

3. Is there a way not to allocate the whole device capacity? Currently I  create a fairly small, 6G VMFS datastore from thin device which can be expanded later. Will only the 6G be allocated? What if we use RDM, does RDM work?

4. If VASA is configured, what different does it make for thin device provision, Datastore creation?

Your inputs are welcomed.