I am trying to finally fulfill my long dream of creating a small blood pact army from my left over grenadiers and I am unsure about some things. I would be really greatful for any help, because the only things that stand between me and the army are the answers to these questions.

First off, can the force be lead by a simple rogue psyker with access to chaos armory and psykic powers?

If not, can it be led by a simple imperial psyker with access to imperial armory?

Are all imperial units fair game to be taken for blood pact, meaning basilisks, hellhounds and sentinels?

If commanded by an imperial psyker (NOT A CHAOS LORD) can the blood pact benefit from imperial doctrines?