Are tile bonuses counted twice if 2 new words are formed?
Yes, you score it twice as long as the double/triple letter/word tile was covered up by your current play.

From the rules:


  When two or more words are formed in the same play, each is scored. The common letter is counted (with full premium value, if any) for each word. (See Turns 3, 4 and 5 in the Scoring Examples