When create a service profile, you can assign the desired power state of the server in the server assignment section.
You can view the desired power state of a service profile in General > status section.
NOTE There is a typo in the doc where it says that this config is applied before associating the service profile. The action takes place after associating the service profile and not before.
Yes, BIOS policy has this option but I believe initial / desired powered state in service profile would supersede this configuration option.
To my knowledge you cannot set the Service Profile power behavior after an AC power loss. You can the the "down" option during profile creation and this will power down the server after association but does does not help you after an AC power loss.
To my knowledge the BIOs policy is the only way.