"Once the vSAN is configured the first time it is FFT1 standard, right?"
Default vSAN Storage Policy is FTT=1,FTM=RAID1 (Fault Tolerance Method).
"Is the FTT type definition based on the policy configured in the VMs?"
Yes, the rules of the Storage Policy applied to the VM (or its sub-components e.g. vmdks) dictate their attributes.
"Is there a vSAN configuration that includes scenario with FTT and type of RAID? Or is FTT RAID the same configuration?"
Not sure I understand what you mean - FTT dictates the number of failures an Object can tolerate and still be accessible, FTM dictates how these are stored (e.g. RAID1 is standard mirroring + witness component (requires 3 nodes), RAID5 uses 3 data components + parity component (requires 4 nodes and All-Flash, uses less space for the same FTT but is not as high performance).
Welcome to Communities.
Yes the 'Default vSAN Storage Policy' (the only SP automatically created for vSAN) uses FTT=1, FTM=RAID1 by default.
Note however that this (and any other SP) can be modified, best practice is to not modify this SP but to just create a new one with new rule sets.