Henry Block and self Cat Balou in Bang
I have not seen an offical answer or FAQ on this topic but I do know that there is another answer on this site that references playing a bang against yourself which says that is not possible. That answer references a post elsewhere which it says is from the developer that says the rule is in place to prevent unfair behavior.
Post

As I said, the &quot;no-killing-yourself&quot; rule is the official one to prevent unfairy behaviours in tournaments.
However, if you sure to play with fair people, you can allow self-shot, which adds strategic elements to the game as well (think of Bart Cassidy, for example).

Answer where the information came from
What I get from that is if you play a Panic or Cat Balou on yourself as Henry Block you will not have a bang shot at you.