Hawk HP Plus are a street/track pad. They will be fine.

If it's only a lap or two Castrol SRF will be a waste of money. It's $64/quart as opposed to Valvoline DOT 4 which is about $8 and will probably suffice. But again, it depends on the format.

Long sessions = Castrol.
Short runs = DOT 4.

In any case, change your fluid within one week of the event. The day before if possible. Brake fluid absorbs moisture as soon as it's exposed.