favorite style of combat? Well, due to her stunning disposition, I would assume that it would read as "Blow it up.", closely followed by "Blow it up more!" If forced into melee combat, spear made of nuclear fire. The reason for these is twofold: Explosions are a GREAT fear tactic, causing massive morale damage to anyone who can see their allies being nuked, and heat tends to propagate quite well through almost any defense known to man.
Her favorite tactic used in warfare? Cause as many explosions as needed in order to cause the opponents to become soot stains. This would be preferable because explosions are always exciting and as such, it will keep the readers very interested in what goes on in the story. in tactics, it would help because blowing things up early and often tends to both solve the immediate problem as well as cause sufficient fear in those who would cause you problems that they would not cause you problems. There is also a lot of reaction to be had by turning the person next to an enemy into a smoking crater.
Her favorite board game? Battleship: Real World Edition. This would be because it is the only board game which allows the player to blow up real battleships. This would help her discover new and improved methods of focusing the explosions of her cannon, thus giving bonuses to her already formidable, if inelegant, skillset. If this is not allowed, then Mouse Trap. This one is simply because it is the greatest board game ever created.