Greaper's flag "to the left of a nasty talon" is in the crossword grid for the mean version of the Bird puzzle. In the bottom row, in the black cell next to the entry that represents the bird's feet, is a black letter N.
The Big Boo's flag "north of the Land of Enchantment" refers to the Map puzzle which has clues for various southern US states. On the top of the hex representing New Mexico is a letter A in the same color as the page background (or, if viewed in a mobile browser, very slightly different from the page background).
Dry Bones's flag "in a tip for a moniker" is in the hints for the Name puzzle, where there's an extra letter P.
The prize that you really need is a NAP.