What type of clause is shown in parentheses. you all had to wait for whatever the surprise was going be?

The clause in parentheses "(whatever the surprise was going to be)" is a noun clause.

Here's why:

* It functions as the object of the preposition "for". The sentence is saying you all had to wait "for something." That "something" is defined by the noun clause.

* It contains a subject ("the surprise") and a verb ("was going to be"). This is a characteristic of clauses.

Let me know if you'd like to explore other types of clauses!