Bears, such as the Viking bear, can give you bonuses when you play letters.
Is this bonus applied only when all letters appear together or separately?
Reading through SpryFox's AlphaBear game documentation, tells me that the bonus is applied to each letter.
Therefore for the Viking Bear who adds a bonus to "H", "O", "R", and "N", if you play any of those letters, then you receive a bonus. If you play multiple of the bonus letters (i.e. 2 "O"'s, or an "H" and an "N"), then the bonus is applied to each letter.
In fact, the scoring and bonuses are calculated based on letters used, not the word.